SOLUTION: Dear Math Tutor, Please help me express x^2-8x+12 in completed square form . x^2-8x+4-4+12 I got (x-4)^2+8 but my textbook says (x-4)^2-4? where did i go wrong? with grati

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Dear Math Tutor, Please help me express x^2-8x+12 in completed square form . x^2-8x+4-4+12 I got (x-4)^2+8 but my textbook says (x-4)^2-4? where did i go wrong? with grati      Log On


   

Question 878264: Dear Math Tutor,
Please help me express x^2-8x+12 in completed square form .
x^2-8x+4-4+12
I got (x-4)^2+8 but my textbook says (x-4)^2-4?
where did i go wrong?
with gratitude,
Nat

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
In x%5E2-8x%2B12
The first two terms, x%5E2-8x ,
remind you of
%28x-4%29%5E2 .
Your error is that
%28x-4%29%5E2=x%5E2-8x%2B4%5E2=x%5E2-8x%2B16 .
So x%5E2-8x%2B12=x%5E2-8x%2B16-16%2B12=%28x-4%29%5E2-16%2B12=%28x-4%29%5E2-4
You forgot to square the 4 ,
as if %28x-4%29%5E2 was x%5E2-8x%2B4 .