Question

What values of x would make the following equation true?

Answer 1

x^2-4x+5=8  so let's complete the square, subtract 5 from both sides

x^2-4x=3  halve the linear coefficient, square it, and add it to both sides...(-4/2)^2=4

x^2-4x+4=7  now the left side is a perfect square of the form

(x-2)^2=7  take the square root of both sides

x-2=±√7  add 2 to both sides

x=2±√7

So A. is your answer.