Question

Max rewrote the function f(x) = 4x²+16x+8 in vertex form by completing the square. 2
He concluded that the vertex is (-2, 4), which was incorrect. Consider Max's work, listed below.
In which step did Max make a mistake?
Step 1:f(x) = 4x² + 16x +8
Step 2: f(x) = 4(x²+4x) +8
Step 3: f(x) = 4(x²+4x+4)+8-4
Step 4: f(x) = 4(x+2)²+4

Answer 1

Max made a mistake in Step 3 when he incorrectly subtracted 4 from 8 in the equation f(x) = 4(x²+4x+4)+8-4. Instead, he should have subtracted 4 from the term inside the parentheses, resulting in f(x) = 4(x²+4x+4)+8-4x.