Question

Use the quadratic formula to solve the equation 2x^2+2x-4=0

Answer 1

Answer:

x = -2 or x = 1

Step-by-step explanation:

The quadratic formula for the quadratic equation ax² + bx + c = 0:

$x=\dfrac{-b\pm\sqrt{b^2-4ac}}{2a}$

$2x^2+2x-4=0\qquad\text{divide both sides by 2}\\\\x^2+x-2=0$

$a=1,\ b=1,\ c=-2$

Substitute:

$x=\dfrac{-1\pm\sqrt{1^2-4(1)(-2)}}{2(1)}=\dfrac{-1\pm\sqrt{9}}{2}=\dfrac{-1\pm3}{2}\\\\x_1=\dfrac{-1-3}{2}=\dfrac{-4}{2}=-2\\\\x_2=\dfrac{-1+3}{2}=\dfrac{2}{2}=1$