(-6x+36)(5x+25)=0

Solution for (-6x+36)(5x+25)=0 equation:

(-6x+36)(5x+25)=0

We multiply parentheses ..

(-30x^2-150x+180x+900)=0

We get rid of parentheses

-30x^2-150x+180x+900=0

We add all the numbers together, and all the variables

-30x^2+30x+900=0

a = -30; b = 30; c = +900;
Δ = b2-4ac
Δ = 302-4·(-30)·900
Δ = 108900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{108900}=330$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-330}{2*-30}=\frac{-360}{-60}
=+6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+330}{2*-30}=\frac{300}{-60}
=-5
$