15x^2-165x-70=0

Solution for 15x^2-165x-70=0 equation:

15x^2-165x-70=0

a = 15; b = -165; c = -70;
Δ = b2-4ac
Δ = -1652-4·15·(-70)
Δ = 31425
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{31425}=\sqrt{25*1257}=\sqrt{25}*\sqrt{1257}=5\sqrt{1257}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-165)-5\sqrt{1257}}{2*15}=\frac{165-5\sqrt{1257}}{30}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-165)+5\sqrt{1257}}{2*15}=\frac{165+5\sqrt{1257}}{30}
$