12-x=20-x2

Solution for 12-x=20-x2 equation:

12-x=20-x2

We move all terms to the left:

12-x-(20-x2)=0

We add all the numbers together, and all the variables

-(-1x^2+20)-x+12=0

We add all the numbers together, and all the variables

-(-1x^2+20)-1x+12=0

We get rid of parentheses

1x^2-1x-20+12=0

We add all the numbers together, and all the variables

x^2-1x-8=0

a = 1; b = -1; c = -8;
Δ = b2-4ac
Δ = -12-4·1·(-8)
Δ = 33
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-\sqrt{33}}{2*1}=\frac{1-\sqrt{33}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+\sqrt{33}}{2*1}=\frac{1+\sqrt{33}}{2}
$