Question

I don't understand how b, c or, d were gotten. Ive tried multiplication, addition etc.

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Answer 1

\(\large\rm f=2x\qquad\qquad\qquad g=x+9\)

So in b they want us to take f and stick it inside of g.
\(\large\rm g\circ f=f+9\)
Do you understand what I did?
I took the x which was in our g function,
and replaced it with f.
Now as a final step, let's replace the letter f with it's equivalent,
\(\large\rm g\circ f=2x+9\)

What do you think?

Answer 2

Composition can be a little tricky.

Answer 3

Thanks. I will read over what you showed me carefully.

Answer 4

For part d,
you would do the same thing as part b,
but then as a final step, plug in x=2.