-5x(x+7)=5x+35

Solution for -5x(x+7)=5x+35 equation:

-5x(x+7)=5x+35

We move all terms to the left:

-5x(x+7)-(5x+35)=0

We multiply parentheses

-5x^2-35x-(5x+35)=0

We get rid of parentheses

-5x^2-35x-5x-35=0

We add all the numbers together, and all the variables

-5x^2-40x-35=0

a = -5; b = -40; c = -35;
Δ = b2-4ac
Δ = -402-4·(-5)·(-35)
Δ = 900
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{900}=30$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-40)-30}{2*-5}=\frac{10}{-10}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-40)+30}{2*-5}=\frac{70}{-10}
=-7
$