Year 11 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 2 — 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 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) = 3x2 + 6x + 9, find f(4).
Answer: 81
- Replace x with 4: 3(4)2 + 6(4) + 9
- = 81
2.If f(x) = 2x − 7, find f(−3).
Answer: −13
- Replace x with −3: 2(−3) − 7
- = −13
3.If f(x) = 2x2 − 3x − 9, find f(4).
Answer: 11
- Replace x with 4: 2(4)2 − 3(4) − 9
- = 11
4.If f(x) = 6x + 4, find f(5).
Answer: 34
- Replace x with 5: 6(5) + 4
- = 34
5.If f(x) = 4x2 + 7, find f(−2).
Answer: 23
- Replace x with −2: 4(−2)2 + 7
- = 23
6.If f(x) = −6x + 6, find f(5).
Answer: −24
- Replace x with 5: −6(5) + 6
- = −24
7.If f(x) = 3x2 − x − 9, find f(−4).
Answer: 43
- Replace x with −4: 3(−4)2 − (−4) − 9
- = 43
8.If f(x) = 3x + 8, find f(5).
Answer: 23
- Replace x with 5: 3(5) + 8
- = 23
9.If f(x) = 2x2 + 6x + 3, find f(−2).
Answer: −1
- Replace x with −2: 2(−2)2 + 6(−2) + 3
- = −1
10.If f(x) = 2x2 + 5x + 1, find f(−4).
Answer: 13
- Replace x with −4: 2(−4)2 + 5(−4) + 1
- = 13
11.If f(x) = −3x2 + 4, find f(4).
Answer: −44
- Replace x with 4: −3(4)2 + 4
- = −44
12.If f(x) = −2x + 6, find f(−1).
Answer: 8
- Replace x with −1: −2(−1) + 6
- = 8
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