Answer:
f(u +6) = u
Step-by-step explanation:
Put (u+6) in place of t and simplify:
f(u+6) = (u+6) -6
f(u+6) = u
I believe the answer is 9 years old or 8 years old.
I think D because it seems the most reasonable
<em>Answer:</em>
–6.8
<em>Method:</em>
Counting backwards from –7 to –6.5