X=x^2-10x+18

Solution for X=x^2-10x+18 equation:

X=X^2-10X+18

We move all terms to the left:

X-(X^2-10X+18)=0

We get rid of parentheses

-X^2+X+10X-18=0

We add all the numbers together, and all the variables

-1X^2+11X-18=0

a = -1; b = 11; c = -18;
Δ = b2-4ac
Δ = 112-4·(-1)·(-18)
Δ = 49
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{49}=7$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-7}{2*-1}=\frac{-18}{-2}
=+9
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+7}{2*-1}=\frac{-4}{-2}
=+2
$