(2x+20)(2x+30)=375

Solution for (2x+20)(2x+30)=375 equation:

(2x+20)(2x+30)=375

We move all terms to the left:

(2x+20)(2x+30)-(375)=0

We multiply parentheses ..

(+4x^2+60x+40x+600)-375=0

We get rid of parentheses

4x^2+60x+40x+600-375=0

We add all the numbers together, and all the variables

4x^2+100x+225=0

a = 4; b = 100; c = +225;
Δ = b2-4ac
Δ = 1002-4·4·225
Δ = 6400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{6400}=80$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(100)-80}{2*4}=\frac{-180}{8}
=-22+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(100)+80}{2*4}=\frac{-20}{8}
=-2+1/2
$