15x^2+13x=20

Solution for 15x^2+13x=20 equation:

15x^2+13x=20

We move all terms to the left:

15x^2+13x-(20)=0

a = 15; b = 13; c = -20;
Δ = b2-4ac
Δ = 132-4·15·(-20)
Δ = 1369
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1369}=37$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(13)-37}{2*15}=\frac{-50}{30}
=-1+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(13)+37}{2*15}=\frac{24}{30}
=4/5
$