(x^2-9x)+(7x+12)=180

Solution for (x^2-9x)+(7x+12)=180 equation:

(x^2-9x)+(7x+12)=180

We move all terms to the left:

(x^2-9x)+(7x+12)-(180)=0

We get rid of parentheses

x^2-9x+7x+12-180=0

We add all the numbers together, and all the variables

x^2-2x-168=0

a = 1; b = -2; c = -168;
Δ = b2-4ac
Δ = -22-4·1·(-168)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-2)-26}{2*1}=\frac{-24}{2}
=-12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-2)+26}{2*1}=\frac{28}{2}
=14
$