(2x+5)(x+5)=325

Solution for (2x+5)(x+5)=325 equation:

(2x+5)(x+5)=325

We move all terms to the left:

(2x+5)(x+5)-(325)=0

We multiply parentheses ..

(+2x^2+10x+5x+25)-325=0

We get rid of parentheses

2x^2+10x+5x+25-325=0

We add all the numbers together, and all the variables

2x^2+15x-300=0

a = 2; b = 15; c = -300;
Δ = b2-4ac
Δ = 152-4·2·(-300)
Δ = 2625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{2625}=\sqrt{25*105}=\sqrt{25}*\sqrt{105}=5\sqrt{105}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-5\sqrt{105}}{2*2}=\frac{-15-5\sqrt{105}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+5\sqrt{105}}{2*2}=\frac{-15+5\sqrt{105}}{4}
$