(x*x)-18x=90x

Solution for (x*x)-18x=90x equation:

(x*x)-18x=90x

We move all terms to the left:

(x*x)-18x-(90x)=0

We add all the numbers together, and all the variables

(+x*x)-18x-90x=0

We add all the numbers together, and all the variables

-108x+(+x*x)=0

We get rid of parentheses

-108x+x*x=0

Wy multiply elements

x^2-108x=0

a = 1; b = -108; c = 0;
Δ = b2-4ac
Δ = -1082-4·1·0
Δ = 11664
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{11664}=108$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-108)-108}{2*1}=\frac{0}{2}
=0
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-108)+108}{2*1}=\frac{216}{2}
=108
$