Skip to content
Quadratic Equations
Example 1

Example 1: Quadratic Equation Methods

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

Problem

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

1. Recognize Pattern

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

2. Apply Method

4x2+56x+196=0⇒x∈{−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
Next exampleBack to lessonsPractice this skillTry in calculator