-8x^2+19x+15=0

Solution for -8x^2+19x+15=0 equation:

-8x^2+19x+15=0

a = -8; b = 19; c = +15;
Δ = b2-4ac
Δ = 192-4·(-8)·15
Δ = 841
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{841}=29$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-29}{2*-8}=\frac{-48}{-16}
=+3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+29}{2*-8}=\frac{10}{-16}
=-5/8
$