Year 11 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 4 — Answers
Answer sheet with worked solutions for the Year 11 functions worksheet.
Success TutoringWorksheetsAnswer sheetYear 11 · Mathematics · FunctionsYear 11 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 4 — 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) = 2x2 − 2x − 7, find f(−3).
Answer: 17
- Replace x with −3: 2(−3)2 − 2(−3) − 7
- = 17
2.If f(x) = 4x − 5, find f(1).
Answer: −1
- Replace x with 1: 4(1) − 5
- = −1
3.If f(x) = 2x + 8, find f(−4).
Answer: 0
- Replace x with −4: 2(−4) + 8
- = 0
4.If f(x) = 2x − 9, find f(2).
Answer: −5
- Replace x with 2: 2(2) − 9
- = −5
5.If f(x) = −2x2 − 5x − 7, find f(3).
Answer: −40
- Replace x with 3: −2(3)2 − 5(3) − 7
- = −40
6.If f(x) = −2x2 + 6x + 9, find f(2).
Answer: 13
- Replace x with 2: −2(2)2 + 6(2) + 9
- = 13
7.If f(x) = −x2 − 3x − 6, find f(2).
Answer: −16
- Replace x with 2: −(2)2 − 3(2) − 6
- = −16
8.If f(x) = 4x2 − x − 6, find f(2).
Answer: 8
- Replace x with 2: 4(2)2 − (2) − 6
- = 8
9.If f(x) = −3x2 − 3x + 4, find f(4).
Answer: −56
- Replace x with 4: −3(4)2 − 3(4) + 4
- = −56
10.If f(x) = −2x − 8, find f(−4).
Answer: 0
- Replace x with −4: −2(−4) − 8
- = 0
11.If f(x) = 4x + 7, find f(5).
Answer: 27
- Replace x with 5: 4(5) + 7
- = 27
12.If f(x) = 3x2 + 6x − 5, find f(−1).
Answer: −8
- Replace x with −1: 3(−1)2 + 6(−1) − 5
- = −8
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