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

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

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

We move all terms to the left:

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

We multiply parentheses

25x^2-150x-180=0

a = 25; b = -150; c = -180;
Δ = b2-4ac
Δ = -1502-4·25·(-180)
Δ = 40500
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{40500}=\sqrt{8100*5}=\sqrt{8100}*\sqrt{5}=90\sqrt{5}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-150)-90\sqrt{5}}{2*25}=\frac{150-90\sqrt{5}}{50}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-150)+90\sqrt{5}}{2*25}=\frac{150+90\sqrt{5}}{50}
$