2x^2+8x=100

Solution for 2x^2+8x=100 equation:

2x^2+8x=100

We move all terms to the left:

2x^2+8x-(100)=0

a = 2; b = 8; c = -100;
Δ = b2-4ac
Δ = 82-4·2·(-100)
Δ = 864
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:

$\sqrt{\Delta}=\sqrt{864}=\sqrt{144*6}=\sqrt{144}*\sqrt{6}=12\sqrt{6}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-12\sqrt{6}}{2*2}=\frac{-8-12\sqrt{6}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+12\sqrt{6}}{2*2}=\frac{-8+12\sqrt{6}}{4}
$