7x^2+12=-20x

Solution for 7x^2+12=-20x equation:

7x^2+12=-20x

We move all terms to the left:

7x^2+12-(-20x)=0

We get rid of parentheses

7x^2+20x+12=0

a = 7; b = 20; c = +12;
Δ = b2-4ac
Δ = 202-4·7·12
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-8}{2*7}=\frac{-28}{14}
=-2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+8}{2*7}=\frac{-12}{14}
=-6/7
$