-6b2+60b+100=0

Solution for -6b2+60b+100=0 equation:

-6b^2+60b+100=0

a = -6; b = 60; c = +100;
Δ = b2-4ac
Δ = 602-4·(-6)·100
Δ = 6000
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:

$\sqrt{\Delta}=\sqrt{6000}=\sqrt{400*15}=\sqrt{400}*\sqrt{15}=20\sqrt{15}$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(60)-20\sqrt{15}}{2*-6}=\frac{-60-20\sqrt{15}}{-12}
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(60)+20\sqrt{15}}{2*-6}=\frac{-60+20\sqrt{15}}{-12}
$