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Quadratic Equations
Example 1

Example 1: Quadratic Equation Methods

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

Problem

Sum of roots for 2x2+2x40=0 is ?\text{Sum of roots for }2x^2+2x-40=0\text{ is }?

1. Recognize Pattern

x=b±b24ac2ax=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

2. Apply Method

4x2+56x+196=0x{7,7}4x^2+56x+196=0\Rightarrow x\in\left\{-7,-7\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