180=(5x-25)(3x-9)

Solution for 180=(5x-25)(3x-9) equation:

180=(5x-25)(3x-9)

We move all terms to the left:

180-((5x-25)(3x-9))=0

We multiply parentheses ..

-((+15x^2-45x-75x+225))+180=0


We calculate terms in parentheses: -((+15x^2-45x-75x+225)), so:

(+15x^2-45x-75x+225)

We get rid of parentheses

15x^2-45x-75x+225

We add all the numbers together, and all the variables

15x^2-120x+225

Back to the equation:

-(15x^2-120x+225)


We get rid of parentheses

-15x^2+120x-225+180=0

We add all the numbers together, and all the variables

-15x^2+120x-45=0

a = -15; b = 120; c = -45;
Δ = b2-4ac
Δ = 1202-4·(-15)·(-45)
Δ = 11700
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:

$\sqrt{\Delta}=\sqrt{11700}=\sqrt{900*13}=\sqrt{900}*\sqrt{13}=30\sqrt{13}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(120)-30\sqrt{13}}{2*-15}=\frac{-120-30\sqrt{13}}{-30}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(120)+30\sqrt{13}}{2*-15}=\frac{-120+30\sqrt{13}}{-30}
$