X2+13x-20=10

Solution for X2+13x-20=10 equation:

X2+13X-20=10

We move all terms to the left:

X2+13X-20-(10)=0

We add all the numbers together, and all the variables

X^2+13X-30=0

a = 1; b = 13; c = -30;
Δ = b2-4ac
Δ = 132-4·1·(-30)
Δ = 289
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{289}=17$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-17}{2*1}=\frac{-30}{2}
=-15
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+17}{2*1}=\frac{4}{2}
=2
$