x^2+15x=39

Solution for x^2+15x=39 equation:

x^2+15x=39

We move all terms to the left:

x^2+15x-(39)=0

a = 1; b = 15; c = -39;
Δ = b2-4ac
Δ = 152-4·1·(-39)
Δ = 381
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{-(15)-\sqrt{381}}{2*1}=\frac{-15-\sqrt{381}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+\sqrt{381}}{2*1}=\frac{-15+\sqrt{381}}{2}
$