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Quadratic Equations
Example 6

Example 6: Quadratic Equation Methods

Step-by-step worked example for this lesson track.

Problem

Sum of roots for x2−x−30=0 is ?\text{Sum of roots for }x^2-x-30=0\text{ is }?

1. Recognize Pattern

x=−b±b2−4ac2ax=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

2. Apply Method

4x2+36x+80=0⇒x∈{−4,−5}4x^2+36x+80=0\Rightarrow x\in\left\{-4,-5\right\}

3. Conclude

r1+r2=−ba=1r_1+r_2=-\frac{b}{a}=1

Final answer

r1+r2=−ba=1r_1+r_2=-\frac{b}{a}=1
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