x^2+5x=123

Solution for x^2+5x=123 equation:

x^2+5x=123

We move all terms to the left:

x^2+5x-(123)=0

a = 1; b = 5; c = -123;
Δ = b2-4ac
Δ = 52-4·1·(-123)
Δ = 517
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-\sqrt{517}}{2*1}=\frac{-5-\sqrt{517}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+\sqrt{517}}{2*1}=\frac{-5+\sqrt{517}}{2}
$