X^2+13x-15=10

Solution for X^2+13x-15=10 equation:

X^2+13X-15=10

We move all terms to the left:

X^2+13X-15-(10)=0

We add all the numbers together, and all the variables

X^2+13X-25=0

a = 1; b = 13; c = -25;
Δ = b2-4ac
Δ = 132-4·1·(-25)
Δ = 269
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{-(13)-\sqrt{269}}{2*1}=\frac{-13-\sqrt{269}}{2}
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+\sqrt{269}}{2*1}=\frac{-13+\sqrt{269}}{2}
$