(25+2x)(20+2x)=500

Solution for (25+2x)(20+2x)=500 equation:

(25+2x)(20+2x)=500

We move all terms to the left:

(25+2x)(20+2x)-(500)=0

We add all the numbers together, and all the variables

(2x+25)(2x+20)-500=0

We multiply parentheses ..

(+4x^2+40x+50x+500)-500=0

We get rid of parentheses

4x^2+40x+50x+500-500=0

We add all the numbers together, and all the variables

4x^2+90x=0

a = 4; b = 90; c = 0;
Δ = b2-4ac
Δ = 902-4·4·0
Δ = 8100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{8100}=90$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(90)-90}{2*4}=\frac{-180}{8}
=-22+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(90)+90}{2*4}=\frac{0}{8}
=0
$