5b^2+6b-72=0

Solution for 5b^2+6b-72=0 equation:

5b^2+6b-72=0

a = 5; b = 6; c = -72;
Δ = b2-4ac
Δ = 62-4·5·(-72)
Δ = 1476
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1476}=\sqrt{36*41}=\sqrt{36}*\sqrt{41}=6\sqrt{41}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-6\sqrt{41}}{2*5}=\frac{-6-6\sqrt{41}}{10}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+6\sqrt{41}}{2*5}=\frac{-6+6\sqrt{41}}{10}
$