(X-2)(10-y)=0

Solution for (X-2)(10-y)=0 equation:

(X-2)(10-X)=0

We add all the numbers together, and all the variables

(X-2)(-1X+10)=0

We multiply parentheses ..

(-1X^2+10X+2X-20)=0

We get rid of parentheses

-1X^2+10X+2X-20=0

We add all the numbers together, and all the variables

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

a = -1; b = 12; c = -20;
Δ = b2-4ac
Δ = 122-4·(-1)·(-20)
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{-(12)-8}{2*-1}=\frac{-20}{-2}
=+10
$
$X_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+8}{2*-1}=\frac{-4}{-2}
=+2
$