-10x(x-3)=-9x

Solution for -10x(x-3)=-9x equation:

-10x(x-3)=-9x

We move all terms to the left:

-10x(x-3)-(-9x)=0

We multiply parentheses

-10x^2+30x-(-9x)=0

We get rid of parentheses

-10x^2+30x+9x=0

We add all the numbers together, and all the variables

-10x^2+39x=0

a = -10; b = 39; c = 0;
Δ = b2-4ac
Δ = 392-4·(-10)·0
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(39)-39}{2*-10}=\frac{-78}{-20}
=3+9/10
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(39)+39}{2*-10}=\frac{0}{-20}
=0
$