Question

Follow the process of completing the square to solve x^2 - 10x + 8 = 0.

What is the value of the constant that will be isolated on the right side of the equation in step 3?
answer options are:
a.-32
b.-12
c.-8

Answer 1

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.