5x(x+5)=180

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

5x(x+5)=180

We move all terms to the left:

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

We multiply parentheses

5x^2+25x-180=0

a = 5; b = 25; c = -180;
Δ = b2-4ac
Δ = 252-4·5·(-180)
Δ = 4225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4225}=65$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(25)-65}{2*5}=\frac{-90}{10}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(25)+65}{2*5}=\frac{40}{10}
=4
$