(60-2x)(80-2x)=0

Solution for (60-2x)(80-2x)=0 equation:

(60-2x)(80-2x)=0

We add all the numbers together, and all the variables

(-2x+60)(-2x+80)=0

We multiply parentheses ..

(+4x^2-160x-120x+4800)=0

We get rid of parentheses

4x^2-160x-120x+4800=0

We add all the numbers together, and all the variables

4x^2-280x+4800=0

a = 4; b = -280; c = +4800;
Δ = b2-4ac
Δ = -2802-4·4·4800
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-280)-40}{2*4}=\frac{240}{8}
=30
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-280)+40}{2*4}=\frac{320}{8}
=40
$