-5x(x-10)=-35

Solution for -5x(x-10)=-35 equation:

-5x(x-10)=-35

We move all terms to the left:

-5x(x-10)-(-35)=0

We add all the numbers together, and all the variables

-5x(x-10)+35=0

We multiply parentheses

-5x^2+50x+35=0

a = -5; b = 50; c = +35;
Δ = b2-4ac
Δ = 502-4·(-5)·35
Δ = 3200
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3200}=\sqrt{1600*2}=\sqrt{1600}*\sqrt{2}=40\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-40\sqrt{2}}{2*-5}=\frac{-50-40\sqrt{2}}{-10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+40\sqrt{2}}{2*-5}=\frac{-50+40\sqrt{2}}{-10}
$