Quadratic Equations and Their Roots
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Questions and Answers

What is the value of 'q' if one root of the equation $x^2 + px + 12 = 0$ is 4 and the equation $x^2 + px + q = 0$ has equal roots?

  • 4 (correct)
  • 49/4
  • 12
  • 3
  • For which values of m does the quadratic polynomial $P(x) = x^2 + (m + 5)x + (5m + 1)$ become a perfect square?

  • 7 (correct)
  • 3
  • 8
  • 10
  • What is the required value of $a + b$ if the equations $x - 5x + 5 = 0$ and $x + ax + bx + 5 = 0$ have a common root?

  • 0
  • 4
  • -4 (correct)
  • can't find
  • If the equation $ax^2 + bx + c = 0$ has distinct real roots that are both negative, what must be true about the signs of a, b, and c?

    <p>a, b must be of same sign and opposite to sign of c</p> Signup and view all the answers

    For which range of values does the quadratic $P(x) = x^2 - (2 - p)x + p - 2$ assume both positive and negative values?

    <p>(-¥, 2) ∪ (6, ¥)</p> Signup and view all the answers

    What is the least value of 'a' for which the sum of the squares of the roots of the equation $x^2 - (a - 2)x - a - 1 = 0$ is minimized?

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

    What is the correct interval for x such that the expression $y = 8x - x^2 - 15$ is negative?

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

    For the quadratic polynomial $f(x) = ax^2 + bx + 8$ to be symmetric about the line $x = 2$, what is the value of $2a - b$ if the minimum value of $f(x)$ is 6?

    <p>0</p> Signup and view all the answers

    For which of the following sets of values of 'a' will ƒ(x) = ax + 2x(1 – a) – 4 be negative for exactly three integral values of x?

    <p>(0,2)</p> Signup and view all the answers

    Which equation describes the roots a, b, g, d given the polynomial x – bx + 3 = 0?

    <p>3x4 + bx3 – 1 = 0</p> Signup and view all the answers

    What is the relationship satisfied by f(x) = x2 - 6x + 5 if 1 < x < 2?

    <p>f(x) &gt; 0</p> Signup and view all the answers

    What is the modulus of difference of the roots of the equation x2 + 3x – k = 0 compared to the equation x2 + 3x – 10 = 0?

    <p>Twice the difference of the roots</p> Signup and view all the answers

    For the quadratic equations x2 – 11x + m = 0 and x2 – 14x + 2m = 0 to have a common root, what must be the value of m?

    <p>15</p> Signup and view all the answers

    Which of the following conditions must hold if the equations x2 + bx + c = 0 and bx2 + cx + 1 = 0 have a common root?

    <p>Both A and B</p> Signup and view all the answers

    What can be said about the relationship between the discriminants of equations with roots a + d and b + d?

    <p>B2 - 4AC = a2</p> Signup and view all the answers

    If K1 and K2 are values for which the roots a, b satisfy (a/b) + (b/a) = 4/5, what is the correct expression for (K1/K2) + (K2/K1)?

    <p>8/5</p> Signup and view all the answers

    For the equation $x^2 + 2(a + b + c)x + 3l(ab + bc + ca) = 0$ to have real roots, which condition on l must hold?

    <p>l &lt; 3</p> Signup and view all the answers

    If the equations $ax^2 + bx + c = 0$ and $bx^2 + cx + a = 0$ have a common root, what is the value of $a^3 + b^3 + c^3$ assuming $a ≠ 0$?

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

    Given that $a$ and $b$ are roots of the equation $x^2 + bx + c = 0$ with $c < 0 < b$, what can be inferred about the relationship of $a$ and $b$?

    <p>a &lt; 0 &lt; b &lt; |a|</p> Signup and view all the answers

    If $b > a$, which statement about the roots of the equation $(x - a)(x - b) - 1 = 0$ is accurate?

    <p>One root is in $(- ext{∞}, a)$ and the other in $(b, + ext{∞})</p> Signup and view all the answers

    Which expression does NOT hold good based on the graph of $y = ax^2 + bx + c$?

    <p>b^2 &gt; 4ac</p> Signup and view all the answers

    What is the sum of the solutions for the equation $\frac{x - 2}{x - 4} + 2 = 0$ with $x > 0$?

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

    What is the set of all real numbers $x$ such that $x^2 - |x + 2| + x > 0$ holds true?

    <p>$(- ext{∞}, -2) igcup (2, ext{∞})$</p> Signup and view all the answers

    If $a$ and $b$ are roots of the equation $3x^2 - 9x - l = 0$ with conditions $1 < a < 3$ and $3 < b < 5$, what range must $l$ lie within?

    <p>$(-6, 30)$</p> Signup and view all the answers

    What is the value of $\frac{a_{10} - 2a_{8}}{2a_{9}}$ given that $a_n = a_n - b_n$ for $n \geq 1$?

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

    For which value of $b$ do the equations $x^2 + bx - 1 = 0$ and $x^2 + x + b = 0$ have one root in common?

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

    Which interval is a subset of the set $S$ for values of $a$ such that the quadratic equation $ax^2 - x + a = 0$ has roots $x_1$ and $x_2$ satisfying $|x_1 - x_2| < 1$?

    <p>$(-\frac{1}{5}, 0)$</p> Signup and view all the answers

    If $a_4 = 28$, what is the value of $p + 2q$?

    <p>14</p> Signup and view all the answers

    What is the value of $a_{12}$ if $a_n = pa_n + qb_n$?

    <p>a_{11} + 2a_{10}</p> Signup and view all the answers

    Which of the following conditions must be satisfied for the quadratic equation $ax^2 - x + a = 0$ to have two distinct real roots?

    <p>The discriminant must be positive.</p> Signup and view all the answers

    What is the relationship between the roots $a$ and $b$ in the equation $x^2 - x - 1 = 0$ given that $a \neq b$?

    <p>$a + b = 1$</p> Signup and view all the answers

    What is one necessary condition for the roots $x_1$ and $x_2$ of the quadratic equation $ax^2 - x + a = 0$ to satisfy the inequality $|x_1 - x_2| < 1$?

    <p>The distance between the roots must be less than 1.</p> Signup and view all the answers

    What is the value of $c$ in the equation $3b = \frac{1}{2}$?

    <p>1.5</p> Signup and view all the answers

    In the equation $acx^2 - bx + 1 = 0$, what is the term that adjusts the linear coefficient?

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

    Which of the following represents a valid range for $x$ extricated from $x \in (3, \infty)$?

    <p>(3.1, 4)</p> Signup and view all the answers

    From the expression $x^2 - 2(p^2 - 2q)x + p^2(p^2 - 4q) = 0$, which term is key to determining the quadratic's properties?

    <p>$-2(p^2 - 2q)$</p> Signup and view all the answers

    Which expression signifies a quadratic function derived from the variable transformation when $p$ influences $q$?

    <p>$p(p^2 - 5p^2q + 5q^2)$</p> Signup and view all the answers

    What is the solution for $x$ when it lies in the interval $[-2,3)$?

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

    In the equation $x \in R - (0, 1]$, which of the following intervals is NOT included in the solution?

    <p>(0, 1)</p> Signup and view all the answers

    Which of the following cases correctly represents range $[20/9, 4) \cup (5, \infty)$?

    <p>Values between $20/9$ and $4$ or greater than $5$</p> Signup and view all the answers

    Study Notes

    Quadratic Equations and Their Roots

    • Common Root: If two quadratic equations have a common root, then the value of the common root can be found by solving the system of equations.
    • Discriminant: The discriminant of a quadratic equation ax² + bx + c = 0 is b² - 4ac. It helps determine the nature of the roots:
      • If b² - 4ac > 0, the equation has two distinct real roots.
      • If b² - 4ac = 0, the equation has one real root (a double root).
      • If b² - 4ac < 0, the equation has two complex roots.
    • Sum and Product of Roots: For a quadratic equation ax² + bx + c = 0,
      • The sum of the roots is -b/a.
      • The product of the roots is c/a.
    • Quadratic Formula: The roots of the quadratic equation ax² + bx + c = 0 are given by the quadratic formula:
      • x = (-b ± √(b² - 4ac)) / 2a
    • Perfect Square: A quadratic expression is a perfect square if it can be factored as (ax + b)² or (ax - b)².
    • Inequalities:
      • To find the solution set for an inequality involving a quadratic expression, analyze the sign of the expression in different intervals defined by the roots of the quadratic equation.
      • If the leading coefficient of the quadratic expression is positive, the expression is positive outside the interval defined by the roots and negative inside the interval.
      • If the leading coefficient of the quadratic expression is negative, the expression is negative outside the interval defined by the roots and positive inside the interval.

    Specific Equation Solving Techniques

    • Sum and Product of Roots for Solving Systems: Use the sum and product of roots relationships to solve systems of equations involving quadratic equations.
    • Conditions for Specific Root Relationships:
      • Equal Roots: For a quadratic equation ax² + bx + c = 0, the roots are equal if and only if b² - 4ac = 0.
      • Distinct Real Roots: The quadratic ax² + bx + c = 0 has distinct real roots if and only if b² - 4ac > 0.
      • Negative Roots: The quadratic equation ax² + bx + c = 0 has both roots negative if:
        • a, b, and c are all of the same sign (positive or negative)
        • The discriminant b² - 4ac is positive
        • -b/a (the sum of the roots) is negative
        • c/a (the product of the roots ) is positive
    • Factoring for Solution: If possible, factor the quadratic expression to find the roots.

    Additional Notes

    • Graphs: The graph of a quadratic function is a parabola. The shape of the parabola depends on the sign of the leading coefficient.
      • If the leading coefficient is positive, the parabola opens upwards.
      • If the leading coefficient is negative, the parabola opens downwards.
    • Vertex: The vertex of a parabola is the point where the graph changes direction.
      • The x-coordinate of the vertex is -b/2a.
    • Minimum/Maximum Values: The minimum or maximum value of a quadratic function is attained at the vertex.
      • The function has a minimum value if the parabola opens upwards.
      • The function has a maximum value if the parabola opens downwards.
    • Symmetry: The graph of a quadratic function is symmetric about the vertical line passing through the vertex.
    • Transformations: Quadratic functions can be transformed by shifting, stretching, and reflecting their graphs.

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    Description

    Explore the fundamental concepts of quadratic equations including common roots, discriminants, and the quadratic formula. This quiz covers the nature of roots and their sums and products, ensuring a comprehensive understanding of the topic. Test your knowledge and problem-solving skills regarding various aspects of quadratic equations.

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