7b^2=-56b

Solution for 7b^2=-56b equation:

7b^2=-56b

We move all terms to the left:

7b^2-(-56b)=0

We get rid of parentheses

7b^2+56b=0

a = 7; b = 56; c = 0;
Δ = b2-4ac
Δ = 562-4·7·0
Δ = 3136
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3136}=56$
$b_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(56)-56}{2*7}=\frac{-112}{14}
=-8
$
$b_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(56)+56}{2*7}=\frac{0}{14}
=0
$