Answer:
(x-4)^2 [I assume the (z+4)² option was mistyped. Who wants zzzzzzzzz?]
Explanation:
x² − 8x+16
Lok for a pattern that would allow us to fill in the missing numbers in
(x+a)*(x+b)
We know that a and b must equal +16 when multiplied together. We also know their sum must be -8.
a*b = 16
a+b = -8
Is there anything that ties these numbers together? The number 4 comes to mind: 8 and 16 are known to be friendly to 4. We need the sum to be -8, so lets make the 4 negative and put it into both expressions.
(-4)+(-4) = -8 YES
(-4)*(-4) = 16 YES
Assinging -4 to both a and b produces the factored expression:
(x-4)*(x-4) = x² − 8x+16 YES