Algebra Class 10: Radical Equations and Substitutions

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Questions and Answers

What substitution is used in Problem 1 to simplify the equation?

  • u = 3.5x
  • u = x+3
  • u = √(x+3) (correct)
  • u = √(x-3)

The radical equation in Problem 2 has a solution.

False (B)

What is the critical issue discovered when solving Problem 2?

The original problem has no solution when u is negative.

In Problem 3, the equation is transformed after letting u = √x; the next step is to rewrite x as __________.

<p>u²</p> Signup and view all the answers

Match the following problems to their conclusions:

<p>Problem 1 = No valid solution Problem 2 = No solution due to negative u Problem 3 = One solution is invalid</p> Signup and view all the answers

What is the substituted variable in the equation $x^4 - 5x^2 + 6 = 0$?

<p>u = x^2 (C)</p> Signup and view all the answers

The solution set for the equation $x^4 - 3x^2 + 2 = 0$ is {1, -1, √2, -√2}.

<p>True (A)</p> Signup and view all the answers

What values of x are derived from the equation $x^4 - 5x^2 + 6 = 0$?

<p>±√3, ±√2</p> Signup and view all the answers

The new equation after substituting $u = x^2$ into $x^4 - 5x^2 + 6 = 0$ is $u^2 - 5u + ______ = 0$.

<p>6</p> Signup and view all the answers

Match the following equations with their respective solutions:

<p>x^4 - 5x^2 + 6 = 0 = {√3, -√3, √2, -√2} x^4 - 3x^2 + 2 = 0 = {1, -1, √2, -√2}</p> Signup and view all the answers

Which of the following describes a conditional inequality?

<p>It is true only for specific values of the variable involved. (D)</p> Signup and view all the answers

An absolute inequality is true for all permissible values of the variable involved.

<p>True (A)</p> Signup and view all the answers

What does a parenthesis ')' or '(' signify in interval notation?

<p>values are not included</p> Signup and view all the answers

In set notation, {x ∈ R | x > -2} means x belongs to the set of real numbers such that x is greater than _____ .

<p>-2</p> Signup and view all the answers

Match the following inequalities with their descriptions:

<p>3x + 6 &gt; 0 = conditional inequality 3x² - 6 ≤ 0 = quadratic inequality x ≤ 36 = includes endpoint (-2, ∞) = excludes -2</p> Signup and view all the answers

What is the solution to the inequality 5x - x ≥ x + 9?

<p>x ≤ 3 (D)</p> Signup and view all the answers

The interval notation for the solution x ≥ 6 is (-∞, 6).

<p>False (B)</p> Signup and view all the answers

What is the set notation for the inequality x - 1 ≤ 3x - 9 ≤ 2x + 5?

<p>{x ∈ R | 4 ≤ x ≤ 14}</p> Signup and view all the answers

The interval notation for the inequality 5x - x ≥ x + 9 can be expressed as (-∞, _____].

<p>3</p> Signup and view all the answers

Match the following problems with their solutions:

<p>Problem 1 = x ≤ 3 Problem 2 = x ≥ 6 Problem 3 = 4 ≤ x ≤ 14</p> Signup and view all the answers

What are the critical values found when solving the inequality x² + 2x - 3 > 0?

<p>-3, 1 (C)</p> Signup and view all the answers

The interval (-3, 1) results in a true statement for the inequality x² + 2x - 3 > 0.

<p>False (B)</p> Signup and view all the answers

What is the solution to the inequality x² + 2x - 3 > 0?

<p>x &lt; -3 or x &gt; 1</p> Signup and view all the answers

In the solution process, the inequality x² + 2x - 3 = 0 is factored as (x + ______)(x - ______) = 0.

<p>3, 1</p> Signup and view all the answers

Match the intervals with their results for the inequality x² + 2x - 3 > 0:

<p>(-∞, -3) = TRUE (-3, 1) = FALSE (1, ∞) = TRUE</p> Signup and view all the answers

What is the first step in solving the equation $x^4 - 5x^2 + 4 = 0$?

<p>Substituting $u = x^2$ (B)</p> Signup and view all the answers

The solutions for the quadratic equation $u^2 - 5u + 4 = 0$ are $u = 2$ and $u = 3$.

<p>False (B)</p> Signup and view all the answers

What is the final solution for $x$ when solving the equation $x^4 - 5x^2 + 4 = 0$?

<p>$x = ext{±1, ±2}$</p> Signup and view all the answers

For the equation $x^3 - 2x^2 + x + 1 = 0$, the substitution used was $u = x + _____$.

<p>$1/2$</p> Signup and view all the answers

Which method is primarily used to solve the new quadratic equation after substitution?

<p>Factoring (D)</p> Signup and view all the answers

The equation $x^3 + 3x^2 - 4 = 0$ involves a substitution technique that is unclear.

<p>True (A)</p> Signup and view all the answers

When solving $u^2 - 5u + 4 = 0$, the solutions for $u$ are _____ and _____ .

<p>1, 4</p> Signup and view all the answers

Match the polynomial equations with their corresponding substitution:

<p>$x^4 - 5x^2 + 4 = 0$ = $u = x^2 $x^3 - 2x^2 + x + 1 = 0$ = $u = x + 1/2 $x^3 + 3x^2 - 4 = 0$ = $u = x + ext{unknown}</p> Signup and view all the answers

What is the critical value found when solving the inequality $ rac{2}{3x - 5} le 0$?

<p>5/3 (A)</p> Signup and view all the answers

The solution to the inequality $ rac{2x-5}{x-5} le 3$ includes the point x = 6.

<p>False (B)</p> Signup and view all the answers

What is the resulting inequality after rewriting $ rac{2x-5}{x-5} le 3$?

<p>\frac{(2x - 5) - 3(x-5)}{x - 5} le 0</p> Signup and view all the answers

The test interval used to check the inequality $ rac{2}{3x - 5} le 0$ was __________.

<p>(-∞, 5/3)</p> Signup and view all the answers

Match the critical values to their respective intervals:

<p>5 = (-∞, 5) 10 = (10, ∞) 5/3 = (-∞, 5/3) 0 = (-∞, 5)</p> Signup and view all the answers

Which of the following intervals represents the solution to the inequality $x^2 - x + 6 geq 0$?

<p>(- orall, -2] igcup [3, orall) (C)</p> Signup and view all the answers

The roots of the quadratic equation $x^2 - x + 6 = 0$ are $x = -2$ and $x = 3$.

<p>False (B)</p> Signup and view all the answers

What test point shows the inequality $x^2 - x + 6 geq 0$ is true for the interval $(- orall, -2)$?

<p>x = -3</p> Signup and view all the answers

To solve the inequality $x^2 - x + 6 geq 0$, the first step is to __________ the quadratic.

<p>factor</p> Signup and view all the answers

Match each test point with its corresponding evaluation result for the inequality $x^2 - x + 6 geq 0$:

<p>x = -3 = True x = 0 = False x = 4 = True</p> Signup and view all the answers

What is the first critical value identified in the problem?

<p>5 (B)</p> Signup and view all the answers

The intervals of interest exclude the values where the expression is zero.

<p>False (B)</p> Signup and view all the answers

What is the interval notation for all values less than or equal to 5?

<p>(-∞, 5]</p> Signup and view all the answers

The second critical value identified is __________.

<p>10</p> Signup and view all the answers

Match the intervals with their corresponding expression state:

<p>(-∞, 5] = Expression is negative or zero [5, 10] = Expression is zero [10, ∞) = Expression is positive</p> Signup and view all the answers

Flashcards

Quadratic in Form

An equation that can be rewritten as a standard quadratic equation using a substitution.

Substitution Strategy

A technique for solving equations that isn't immediately solvable. A variable is replaced with a simpler variable.

Solve Quadratic Equation

Find the values of the variable 'u' that make the quadratic equation '0'.

Variable Replacement

Replace a variable, like 'x^2' with a new variable 'u', creating a solvable quadratic equation.

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Solution Set

The complete set of solutions to an equation.

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Solving Radical Equations

Solving equations containing square roots or other radicals.

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Substitution Method

Replacing a radical expression with a new variable to simplify the equation.

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Extraneous Solution

A solution that appears to solve the equation but does not hold true when substituted back into the original equation.

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Radical Function Domain

The set of all possible input values for a radical function, ensuring the expression under the radical is non-negative.

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Valid Solution

A solution that satisfies the original equation and the domain restrictions of the radical function.

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Conditional Inequality

An inequality that is not true for all values of the variable.

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Absolute Inequality

An inequality that is true for all values of the variable.

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Interval Notation ( )

Values are not included in a solution set.

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Interval Notation [ ]

Values are included in a solution set.

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Solving Inequalities

Similar to solving equations, but maintain inequality sign when performing operations.

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Quadratic Equation

An equation where the highest power of the variable is 2.

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Factoring

A method to solve quadratic equations by expressing them as a product of simpler terms.

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Polynomial Equation

An equation of degree greater than 2.

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Solving for x

Finding the value of x that satisfies an equation.

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New Variable (u)

A temporary variable introduced to simplify a complex equation.

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Reversing Substitution

Replacing the new variable (u) with the original variable(s) (x) after solving for u.

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Solving for u

The process of finding the value of u when 'u' is substituted in the equation.

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Linear Inequality

A mathematical statement comparing two expressions using inequality symbols (<, >, ≤, ≥). The solution is a set of values for the variable that makes the statement true.

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Solution to a Linear Inequality

A set of all values that satisfy the inequality. It's usually represented using interval or set notation.

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Interval Notation

A way to represent a solution set using parentheses or brackets. Brackets indicate inclusion of endpoints, parentheses indicate exclusion.

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Set Notation

A way to represent a solution set using curly braces and a description of the values it includes. It uses the symbol '∈' (belongs to) to indicate membership.

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Solve a Linear Inequality

The process of finding the solution set by isolating the variable using operations just like with equations, but being mindful of changing the inequality sign when multiplying or dividing by a negative number.

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Critical Values

The values of the variable that make the quadratic expression equal to zero. These values divide the number line into intervals.

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Test Intervals

The intervals created by the critical values on the number line. These intervals are tested with specific values to determine if they satisfy the inequality.

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Inequality to Equality

The first step in solving quadratic inequalities is to change the inequality sign to an equality sign.

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Why test intervals?

Testing values within each interval helps determine which intervals satisfy the inequality. This is crucial for finding the solution set.

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Rational Inequality

An inequality involving a rational expression, where the variable appears in the denominator.

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Combining Terms

To solve rational inequalities, combine the terms on one side to make the other side equal to zero, then simplify the expression by finding a common denominator.

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Solve Quadratic Inequality

Find the values of 'x' that make the inequality true. Involves factoring, finding roots, and testing intervals.

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Factor the Quadratic

Rewrite the quadratic expression as a product of two linear factors. This step helps find the 'roots' of the quadratic equation.

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Solution Intervals

Express the solution to the inequality using interval notation, indicating where the values of 'x' satisfy the inequality.

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Number Line Graph

Visually represent the solution to the inequality on a number line. Shade the intervals that satisfy the inequality and use appropriate symbols for the endpoints (open or closed circles).

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Interval of Interest

A specific range on the number line that is relevant to the solution of the inequality. It's where the expression is positive or negative, depending on the problem.

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What does this exercise tell us?

The exercise helps determine the intervals where an expression is positive or negative, which indicates whether the graph of the function lies above or below the x-axis in those intervals.

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Why are critical values important?

Critical values are key because they help define the intervals where the expression is positive, negative, or undefined. These intervals are essential for solving inequalities and understanding the function's behavior.

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