2b^2+15b-17=0

Solution for 2b^2+15b-17=0 equation:

2b^2+15b-17=0

a = 2; b = 15; c = -17;
Δ = b2-4ac
Δ = 152-4·2·(-17)
Δ = 361
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{361}=19$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(15)-19}{2*2}=\frac{-34}{4}
=-8+1/2
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(15)+19}{2*2}=\frac{4}{4}
=1
$