x^2+60x-40=900

Solution for x^2+60x-40=900 equation:

x^2+60x-40=900

We move all terms to the left:

x^2+60x-40-(900)=0

We add all the numbers together, and all the variables

x^2+60x-940=0

a = 1; b = 60; c = -940;
Δ = b2-4ac
Δ = 602-4·1·(-940)
Δ = 7360
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:

$\sqrt{\Delta}=\sqrt{7360}=\sqrt{64*115}=\sqrt{64}*\sqrt{115}=8\sqrt{115}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-8\sqrt{115}}{2*1}=\frac{-60-8\sqrt{115}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+8\sqrt{115}}{2*1}=\frac{-60+8\sqrt{115}}{2}
$