6x-18=X2-8x+15

Solution for 6x-18=X2-8x+15 equation:

6x-18=x2-8x+15

We move all terms to the left:

6x-18-(x2-8x+15)=0

We add all the numbers together, and all the variables

-(+x^2-8x+15)+6x-18=0

We get rid of parentheses

-x^2+8x+6x-15-18=0

We add all the numbers together, and all the variables

-1x^2+14x-33=0

a = -1; b = 14; c = -33;
Δ = b2-4ac
Δ = 142-4·(-1)·(-33)
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(14)-8}{2*-1}=\frac{-22}{-2}
=+11
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+8}{2*-1}=\frac{-6}{-2}
=+3
$