(15-2x)(12-2x)=0

Solution for (15-2x)(12-2x)=0 equation:

(15-2x)(12-2x)=0

We add all the numbers together, and all the variables

(-2x+15)(-2x+12)=0

We multiply parentheses ..

(+4x^2-24x-30x+180)=0

We get rid of parentheses

4x^2-24x-30x+180=0

We add all the numbers together, and all the variables

4x^2-54x+180=0

a = 4; b = -54; c = +180;
Δ = b2-4ac
Δ = -542-4·4·180
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-54)-6}{2*4}=\frac{48}{8}
=6
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-54)+6}{2*4}=\frac{60}{8}
=7+1/2
$