90+(5x-2)+(x^2+8)=180

Solution for 90+(5x-2)+(x^2+8)=180 equation:

90+(5x-2)+(x^2+8)=180

We move all terms to the left:

90+(5x-2)+(x^2+8)-(180)=0

We add all the numbers together, and all the variables

(5x-2)+(x^2+8)-90=0

We get rid of parentheses

x^2+5x-2+8-90=0

We add all the numbers together, and all the variables

x^2+5x-84=0

a = 1; b = 5; c = -84;
Δ = b2-4ac
Δ = 52-4·1·(-84)
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-19}{2*1}=\frac{-24}{2}
=-12
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+19}{2*1}=\frac{14}{2}
=7
$