18b^2-3b-15=0

Solution for 18b^2-3b-15=0 equation:

18b^2-3b-15=0

a = 18; b = -3; c = -15;
Δ = b2-4ac
Δ = -32-4·18·(-15)
Δ = 1089
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1089}=33$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-3)-33}{2*18}=\frac{-30}{36}
=-5/6
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-3)+33}{2*18}=\frac{36}{36}
=1
$