Start with x^2 - 10x + 8 = 0.
Take half of the coefficient of x; that is, take half of -10. Result: -5
Square this -5, and then add the resulting square to x^2 - 10x:
x^2 - 10 x + (-10/2) - (-10/2) = -8
Simplifying, x^2 - 10 x + 25 - 25 = -8
Rewriting: (x-5)^2 = 33
And so on.
The value of the const. that will be isolated on the rt. side of the equation in Step 3 is - 8.
