X^2-400x=-60

Solution for X^2-400x=-60 equation:

X^2-400X=-60

We move all terms to the left:

X^2-400X-(-60)=0

We add all the numbers together, and all the variables

X^2-400X+60=0

a = 1; b = -400; c = +60;
Δ = b2-4ac
Δ = -4002-4·1·60
Δ = 159760
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:

$\sqrt{\Delta}=\sqrt{159760}=\sqrt{16*9985}=\sqrt{16}*\sqrt{9985}=4\sqrt{9985}$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-400)-4\sqrt{9985}}{2*1}=\frac{400-4\sqrt{9985}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-400)+4\sqrt{9985}}{2*1}=\frac{400+4\sqrt{9985}}{2}
$