(x+30)(5x-25)=180

Solution for (x+30)(5x-25)=180 equation:

(x+30)(5x-25)=180

We move all terms to the left:

(x+30)(5x-25)-(180)=0

We multiply parentheses ..

(+5x^2-25x+150x-750)-180=0

We get rid of parentheses

5x^2-25x+150x-750-180=0

We add all the numbers together, and all the variables

5x^2+125x-930=0

a = 5; b = 125; c = -930;
Δ = b2-4ac
Δ = 1252-4·5·(-930)
Δ = 34225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{34225}=185$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(125)-185}{2*5}=\frac{-310}{10}
=-31
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(125)+185}{2*5}=\frac{60}{10}
=6
$