2.5x(x+20)=5x

Solution for 2.5x(x+20)=5x equation:

2.5x(x+20)=5x

We move all terms to the left:

2.5x(x+20)-(5x)=0

We add all the numbers together, and all the variables

-5x+2.5x(x+20)=0

We multiply parentheses

2x^2-5x+40x=0

We add all the numbers together, and all the variables

2x^2+35x=0

a = 2; b = 35; c = 0;
Δ = b2-4ac
Δ = 352-4·2·0
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(35)-35}{2*2}=\frac{-70}{4}
=-17+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(35)+35}{2*2}=\frac{0}{4}
=0
$