Year 12 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 3 — Answers
Answer sheet with worked solutions for the Year 12 functions worksheet.
Success TutoringWorksheetsAnswer sheetYear 12 · Mathematics · FunctionsYear 12 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 3 — Answers
f(x) notation means "the value of the function at x". For a composite, substitute the inner function into the outer one. For an inverse, swap x and y and solve for y.
1.If f(x) = 4x + 1, find f(−4).
Answer: −15
- Replace x with −4: 4(−4) + 1
- = −15
2.If f(x) = 3x − 7, find f(−3).
Answer: −16
- Replace x with −3: 3(−3) − 7
- = −16
3.If f(x) = 3x2 + 6x + 5, find f(−3).
Answer: 14
- Replace x with −3: 3(−3)2 + 6(−3) + 5
- = 14
4.If f(x) = 2x2 − x + 4, find f(2).
Answer: 10
- Replace x with 2: 2(2)2 − (2) + 4
- = 10
5.If f(x) = 4x − 8, find f(−1).
Answer: −12
- Replace x with −1: 4(−1) − 8
- = −12
6.If f(x) = −2x − 1, find f(−1).
Answer: 1
- Replace x with −1: −2(−1) − 1
- = 1
7.If f(x) = 3x + 9, find f(2).
Answer: 15
- Replace x with 2: 3(2) + 9
- = 15
8.If f(x) = 6x + 1, find f(3).
Answer: 19
- Replace x with 3: 6(3) + 1
- = 19
9.If f(x) = −x + 8, find f(0).
Answer: 8
- Replace x with 0: −(0) + 8
- = 8
10.If f(x) = 2x − 7, find f(−2).
Answer: −11
- Replace x with −2: 2(−2) − 7
- = −11
11.If f(x) = x2 + x + 8, find f(3).
Answer: 20
- Replace x with 3: (3)2 + (3) + 8
- = 20
12.If f(x) = 2x + 3, find f(1).
Answer: 5
- Replace x with 1: 2(1) + 3
- = 5
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