Solve the following quadratic equations and find the discriminants: 1) 2x^2 + 7x + 3 = 0, 2) x^2 - 8x + 16 = 0, 3) 2x^2 - 4x + 5 = 0.
Understand the Problem
The question involves solving quadratic equations using the quadratic formula and calculating their discriminants (D) for three different quadratic equations.
Answer
1) $x_1 = -\frac{1}{2}, x_2 = -3$ 2) $x = 4$ 3) No real roots
Answer for screen readers
- Roots: $x_1 = -\frac{1}{2}, x_2 = -3$
- Root: $x = 4$
- No real roots
Steps to Solve
-
Calculate the Discriminant (D) for the First Equation The first equation is $2x^2 + 7x + 3 = 0$. The discriminant is calculated as follows: $$ D = b^2 - 4ac $$ Here, $a = 2$, $b = 7$, and $c = 3$. Thus, $$ D = 7^2 - 4 \cdot 2 \cdot 3 = 49 - 24 = 25 $$
-
Determine the Roots for the First Equation Now use the quadratic formula: $$ x = \frac{-b \pm \sqrt{D}}{2a} $$ Substituting in the values: $$ x_{1,2} = \frac{-7 \pm \sqrt{25}}{2 \cdot 2} = \frac{-7 \pm 5}{4} $$ This leads to two potential solutions: $$ x_1 = \frac{-2}{4} = -\frac{1}{2} $$ $$ x_2 = \frac{-12}{4} = -3 $$
-
Calculate the Discriminant (D) for the Second Equation The second equation is $x^2 - 8x + 16 = 0$. Here, $a = 1$, $b = -8$, and $c = 16$. Calculate the discriminant: $$ D = (-8)^2 - 4 \cdot 1 \cdot 16 = 64 - 64 = 0 $$ Since $D = 0$, this indicates one repeated root.
-
Determine the Root for the Second Equation Using the quadratic formula, we find: $$ x = \frac{-(-8) \pm \sqrt{0}}{2 \cdot 1} = \frac{8}{2} = 4 $$ Thus, the root is $x = 4$.
-
Calculate the Discriminant (D) for the Third Equation The third equation is $2x^2 - 4x + 5 = 0$. Here, $a = 2$, $b = -4$, and $c = 5$. The discriminant is: $$ D = (-4)^2 - 4 \cdot 2 \cdot 5 = 16 - 40 = -24 $$ A negative discriminant indicates no real roots.
- Roots: $x_1 = -\frac{1}{2}, x_2 = -3$
- Root: $x = 4$
- No real roots
More Information
The quadratic formula helps find the roots even for complex solutions. A discriminant of zero means one root, while a negative discriminant indicates complex roots.
Tips
- Forgetting to apply signs correctly when substituting values into the quadratic formula.
- Miscalculating the discriminant; be cautious with the order of operations.
- Not simplifying square roots or fractions completely.
AI-generated content may contain errors. Please verify critical information