-4b2+8b+55=-5

Solution for -4b2+8b+55=-5 equation:

-4b^2+8b+55=-5

We move all terms to the left:

-4b^2+8b+55-(-5)=0

We add all the numbers together, and all the variables

-4b^2+8b+60=0

a = -4; b = 8; c = +60;
Δ = b2-4ac
Δ = 82-4·(-4)·60
Δ = 1024
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1024}=32$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(8)-32}{2*-4}=\frac{-40}{-8}
=+5
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(8)+32}{2*-4}=\frac{24}{-8}
=-3
$