We know that:

Then:

Therefore:

Simplifying the above result we get:

Answer:
Answer:
(a) 9
Step-by-step explanation:

substitute r = 4, t = 2

simplify

cubic of 2 is 8

simplify

Answer:
x = 15
Step-by-step explanation:
If you have any questions about the way I solved it, don't hesitate to ask
Answer:
I'm not 100% sure on this but I think it would be C- 8.1
Step-by-step explanation: