1. The problem is to understand and use the quadratic formula to find the roots of a quadratic equation $ax^2 + bx + c = 0$.
2. The quadratic formula is given by:
$$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$$
This formula calculates the values of $x$ that satisfy the quadratic equation.
3. Important rules:
- The term under the square root, $b^2 - 4ac$, is called the discriminant.
- If the discriminant is positive, there are two real roots.
- If it is zero, there is one real root (a repeated root).
- If it is negative, the roots are complex (not real).
4. To solve a quadratic equation using this formula:
- Identify $a$, $b$, and $c$ from the equation.
- Calculate the discriminant $D = b^2 - 4ac$.
- Substitute $a$, $b$, and $D$ into the formula.
- Simplify to find the roots.
5. Example: Solve $2x^2 + 3x - 2 = 0$.
- Here, $a=2$, $b=3$, $c=-2$.
- Calculate discriminant: $D = 3^2 - 4 \times 2 \times (-2) = 9 + 16 = 25$.
- Substitute into formula:
$$x = \frac{-3 \pm \sqrt{25}}{2 \times 2} = \frac{-3 \pm 5}{4}$$
- Calculate roots:
$$x_1 = \frac{-3 + 5}{4} = \frac{2}{4} = \frac{\cancel{2}}{\cancel{4}} = \frac{1}{2}$$
$$x_2 = \frac{-3 - 5}{4} = \frac{-8}{4} = \frac{\cancel{-8}}{\cancel{4}} = -2$$
6. Final answer: The roots are $x = \frac{1}{2}$ and $x = -2$.
Quadratic Formula 29E016
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