X^2+20x=700

Solution for X^2+20x=700 equation:

X^2+20X=700

We move all terms to the left:

X^2+20X-(700)=0

a = 1; b = 20; c = -700;
Δ = b2-4ac
Δ = 202-4·1·(-700)
Δ = 3200
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:

$\sqrt{\Delta}=\sqrt{3200}=\sqrt{1600*2}=\sqrt{1600}*\sqrt{2}=40\sqrt{2}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(20)-40\sqrt{2}}{2*1}=\frac{-20-40\sqrt{2}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(20)+40\sqrt{2}}{2*1}=\frac{-20+40\sqrt{2}}{2}
$