2x(x+10)=25

Solution for 2x(x+10)=25 equation:

2x(x+10)=25

We move all terms to the left:

2x(x+10)-(25)=0

We multiply parentheses

2x^2+20x-25=0

a = 2; b = 20; c = -25;
Δ = b2-4ac
Δ = 202-4·2·(-25)
Δ = 600
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:

$\sqrt{\Delta}=\sqrt{600}=\sqrt{100*6}=\sqrt{100}*\sqrt{6}=10\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-10\sqrt{6}}{2*2}=\frac{-20-10\sqrt{6}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+10\sqrt{6}}{2*2}=\frac{-20+10\sqrt{6}}{4}
$