-7x(x+7)=-56

Solution for -7x(x+7)=-56 equation:

-7x(x+7)=-56

We move all terms to the left:

-7x(x+7)-(-56)=0

We add all the numbers together, and all the variables

-7x(x+7)+56=0

We multiply parentheses

-7x^2-49x+56=0

a = -7; b = -49; c = +56;
Δ = b2-4ac
Δ = -492-4·(-7)·56
Δ = 3969
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3969}=63$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-49)-63}{2*-7}=\frac{-14}{-14}
=1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-49)+63}{2*-7}=\frac{112}{-14}
=-8
$