15x^2-17x-42=0

Solution for 15x^2-17x-42=0 equation:

15x^2-17x-42=0

a = 15; b = -17; c = -42;
Δ = b2-4ac
Δ = -172-4·15·(-42)
Δ = 2809
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2809}=53$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-17)-53}{2*15}=\frac{-36}{30}
=-1+1/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-17)+53}{2*15}=\frac{70}{30}
=2+1/3
$