Help if you can please!!

Work Shown:

c(b) = 5b

h(b) = b+4

h(c(b)) = c(b)+4 ... replace every b with c(b)

h(c(b)) = 5b+4 ... replace c(b) on the right hand side with 5b

For the sake of simplicity, let's call "h(c(b))" as k

k = h(c(b))

k = 5b+4

that way we can use it later in the next section

a(b) = b^2 + 7

a(k) = k^2 + 7 ... replace b with k

a(k) = (5b+4)^2 + 7 ... plug in k = 5b+4

a(k) = 25b^2+40b+16+7 use FOIL rule

a(k) = 25b^2+40b+23

a( h(c(b)) ) = 25b^2+40b+23

In that last step, I replaced k with h(c(b)) so that we get to the original format your teacher wanted.

based on context clues you gave i'm assuming the answer would be c.

e.

step-by-step explanation:

because there are always 10 numbers in a phone number.