X^2+8x=70

Solution for X^2+8x=70 equation:

X^2+8X=70

We move all terms to the left:

X^2+8X-(70)=0

a = 1; b = 8; c = -70;
Δ = b2-4ac
Δ = 82-4·1·(-70)
Δ = 344
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:

$\sqrt{\Delta}=\sqrt{344}=\sqrt{4*86}=\sqrt{4}*\sqrt{86}=2\sqrt{86}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-2\sqrt{86}}{2*1}=\frac{-8-2\sqrt{86}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+2\sqrt{86}}{2*1}=\frac{-8+2\sqrt{86}}{2}
$