x(2x+5)=525

Solution for x(2x+5)=525 equation:

x(2x+5)=525

We move all terms to the left:

x(2x+5)-(525)=0

We multiply parentheses

2x^2+5x-525=0

a = 2; b = 5; c = -525;
Δ = b2-4ac
Δ = 52-4·2·(-525)
Δ = 4225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4225}=65$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-65}{2*2}=\frac{-70}{4}
=-17+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+65}{2*2}=\frac{60}{4}
=15
$