56+19b-15b^2=0

Solution for 56+19b-15b^2=0 equation:

56+19b-15b^2=0

a = -15; b = 19; c = +56;
Δ = b2-4ac
Δ = 192-4·(-15)·56
Δ = 3721
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3721}=61$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-61}{2*-15}=\frac{-80}{-30}
=2+2/3
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+61}{2*-15}=\frac{42}{-30}
=-1+2/5
$