Marvin was completing the square, and his work is shown below. Identify the line where he made his mistake.

f(x) = 2x2 − 8x + 5
Line 1: f(x) = 2(x2 − 8x) + 5
Line 2: f(x) = 2(x2 − 8x + 16) + 5 − 32
Line 3: f(x) = 2(x − 4)2 − 27

Question

Marvin was completing the square, and his work is shown below. Identify the line where he made his mistake.

f(x) = 2x2 − 8x + 5
Line 1: f(x) = 2(x2 − 8x) + 5
Line 2: f(x) = 2(x2 − 8x + 16) + 5 − 32
Line 3: f(x) = 2(x − 4)2 − 27

anonymous · Answer

Line 1: f(x) = 2(x − 8x) + 5 because 2 wasn't correctly factored out.
It should say f(x) = 2(x2 − 4x + 4) + 5 - 8

anonymous · Answer

ok because when he factored he didn't divide by 2 right

anonymous · Answer

Exactly, you got it.

anonymous · Answer

Can I get a medal?

anonymous · Answer

whats that

anonymous · Answer

A medal is something you give to whoever helped you best. You give a medal by pressing "Best response" on the individual that gave the best answer.