Answer:
2m-9
Step-by-step explanation:
m-4+m-5
=m+m-4-5
=2m-9
Step-by-step explanation:
The given function is :

(a) To find f(9), put x = 9 in the above expression.

(b) To find f(x+7), put x = x+7 in the above expression.

(c) To find f(-x), put x = -x in the above expression.

Hence, this is the required solution.
What do you mean by that?
The answer is B. 2(4) + 3(24) = 80
1(4) + 4(24) = 100