5x(2x+15)=180

Solution for 5x(2x+15)=180 equation:

5x(2x+15)=180

We move all terms to the left:

5x(2x+15)-(180)=0

We multiply parentheses

10x^2+75x-180=0

a = 10; b = 75; c = -180;
Δ = b2-4ac
Δ = 752-4·10·(-180)
Δ = 12825
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:

$\sqrt{\Delta}=\sqrt{12825}=\sqrt{225*57}=\sqrt{225}*\sqrt{57}=15\sqrt{57}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(75)-15\sqrt{57}}{2*10}=\frac{-75-15\sqrt{57}}{20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(75)+15\sqrt{57}}{2*10}=\frac{-75+15\sqrt{57}}{20}
$