Year 11 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 3 — 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 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) = −6x − 8, find f(4).
Answer: −32
- Replace x with 4: −6(4) − 8
- = −32
2.If f(x) = x2 − x + 5, find f(3).
Answer: 11
- Replace x with 3: (3)2 − (3) + 5
- = 11
3.If f(x) = −x2 − 6x + 9, find f(4).
Answer: −31
- Replace x with 4: −(4)2 − 6(4) + 9
- = −31
4.If f(x) = 4x + 2, find f(2).
Answer: 10
- Replace x with 2: 4(2) + 2
- = 10
5.If f(x) = −5x + 1, find f(5).
Answer: −24
- Replace x with 5: −5(5) + 1
- = −24
6.If f(x) = −4x − 8, find f(−1).
Answer: −4
- Replace x with −1: −4(−1) − 8
- = −4
7.If f(x) = −2x + 5, find f(−3).
Answer: 11
- Replace x with −3: −2(−3) + 5
- = 11
8.If f(x) = −x + 9, find f(−3).
Answer: 12
- Replace x with −3: −(−3) + 9
- = 12
9.If f(x) = 5x + 3, find f(−2).
Answer: −7
- Replace x with −2: 5(−2) + 3
- = −7
10.If f(x) = −x2 + x + 9, find f(4).
Answer: −3
- Replace x with 4: −(4)2 + (4) + 9
- = −3
11.If f(x) = −3x2 − 2, find f(0).
Answer: −2
- Replace x with 0: −3(0)2 − 2
- = −2
12.If f(x) = −3x + 3, find f(3).
Answer: −6
- Replace x with 3: −3(3) + 3
- = −6
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