Year 13 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 4 — 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 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) = −3x − 8, find f(3).
Answer: −17
- Replace x with 3: −3(3) − 8
- = −17
2.If f(x) = −3x2 − 4x − 3, find f(−2).
Answer: −7
- Replace x with −2: −3(−2)2 − 4(−2) − 3
- = −7
3.If f(x) = 4x2 + 3, find f(−2).
Answer: 19
- Replace x with −2: 4(−2)2 + 3
- = 19
4.If f(x) = 2x2 + 4x − 3, find f(4).
Answer: 45
- Replace x with 4: 2(4)2 + 4(4) − 3
- = 45
5.If f(x) = −x − 9, find f(−3).
Answer: −6
- Replace x with −3: −(−3) − 9
- = −6
6.If f(x) = −x2 − 5x + 7, find f(0).
Answer: 7
- Replace x with 0: −(0)2 − 5(0) + 7
- = 7
7.If f(x) = −x2 − 2x + 5, find f(−2).
Answer: 5
- Replace x with −2: −(−2)2 − 2(−2) + 5
- = 5
8.If f(x) = 3x2 + 3x − 6, find f(−2).
Answer: 0
- Replace x with −2: 3(−2)2 + 3(−2) − 6
- = 0
9.If f(x) = 4x2 − x + 9, find f(3).
Answer: 42
- Replace x with 3: 4(3)2 − (3) + 9
- = 42
10.If f(x) = 2x + 5, find f(4).
Answer: 13
- Replace x with 4: 2(4) + 5
- = 13
11.If f(x) = −2x2 + x + 4, find f(−4).
Answer: −32
- Replace x with −4: −2(−4)2 + (−4) + 4
- = −32
12.If f(x) = −x2 − 6x − 4, find f(1).
Answer: −11
- Replace x with 1: −(1)2 − 6(1) − 4
- = −11
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