180=5x(x-5)

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

180=5x(x-5)

We move all terms to the left:

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


We calculate terms in parentheses: -(5x(x-5)), so:

5x(x-5)

We multiply parentheses

5x^2-25x

Back to the equation:

-(5x^2-25x)


We get rid of 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
$