X2=22x-21

Solution for X2=22x-21 equation:

X2=22X-21

We move all terms to the left:

X2-(22X-21)=0

We add all the numbers together, and all the variables

X^2-(22X-21)=0

We get rid of parentheses

X^2-22X+21=0

a = 1; b = -22; c = +21;
Δ = b2-4ac
Δ = -222-4·1·21
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$X_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-22)-20}{2*1}=\frac{2}{2}
=1
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-22)+20}{2*1}=\frac{42}{2}
=21
$