Year 13 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 2 — Answers
Answer sheet with worked solutions for the Year 13 functions worksheet.
Success TutoringWorksheetsAnswer sheetYear 13 · Mathematics · FunctionsYear 13 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 2 — 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) = 2x + 8, find f(3).
Answer: 14
- Replace x with 3: 2(3) + 8
- = 14
2.If f(x) = −2x − 7, find f(−3).
Answer: −1
- Replace x with −3: −2(−3) − 7
- = −1
3.If f(x) = 5x − 6, find f(4).
Answer: 14
- Replace x with 4: 5(4) − 6
- = 14
4.If f(x) = −x2 + 5x − 4, find f(−4).
Answer: −40
- Replace x with −4: −(−4)2 + 5(−4) − 4
- = −40
5.If f(x) = −3x2 − x − 9, find f(−3).
Answer: −33
- Replace x with −3: −3(−3)2 − (−3) − 9
- = −33
6.If f(x) = x2 − 5x + 7, find f(−3).
Answer: 31
- Replace x with −3: (−3)2 − 5(−3) + 7
- = 31
7.If f(x) = x2 + 6x − 5, find f(0).
Answer: −5
- Replace x with 0: (0)2 + 6(0) − 5
- = −5
8.If f(x) = x2 + 2x + 7, find f(−1).
Answer: 6
- Replace x with −1: (−1)2 + 2(−1) + 7
- = 6
9.If f(x) = 2x2 − 5x − 6, find f(0).
Answer: −6
- Replace x with 0: 2(0)2 − 5(0) − 6
- = −6
10.If f(x) = −x2 − 5x + 1, find f(5).
Answer: −49
- Replace x with 5: −(5)2 − 5(5) + 1
- = −49
11.If f(x) = x2 − 6x + 9, find f(−1).
Answer: 16
- Replace x with −1: (−1)2 − 6(−1) + 9
- = 16
12.If f(x) = 3x − 8, find f(3).
Answer: 1
- Replace x with 3: 3(3) − 8
- = 1
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