2x^2+31x-8.7=0

Solution for 2x^2+31x-8.7=0 equation:

2x^2+31x-8.7=0

a = 2; b = 31; c = -8.7;
Δ = b2-4ac
Δ = 312-4·2·(-8.7)
Δ = 1030.6
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(31)-\sqrt{1030.6}}{2*2}=\frac{-31-\sqrt{1030.6}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(31)+\sqrt{1030.6}}{2*2}=\frac{-31+\sqrt{1030.6}}{4}
$