LET’S TRY ONE
Let f(x) = 3x − 4 and g(x) = x2. Find f(g(−2)).
8
First g(−2) = 4, then f(4) = 3 × 4 − 4 = 8.
Learning steps & teaching tips
Evaluate an inner function and use its result as the input of an outer function.
- Read f(g(x)) from the inside out; function composition is not multiplication.
- Work through the example. Explain how its evidence supports the answer.
- Try a new question; use the explanation to check your thinking.
Try it together
Write or draw your own example with different numbers. Solve it, then ask a partner to check the method as well as the answer.
Read f(g(x)) from the inside out; function composition is not multiplication.