Question

Help if you can please!!

Answer 1

Answer: Choice (B)

25b^2+40b+23

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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

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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.