Year 13 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 3 — 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 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(−2).
Answer: −20
- Replace x with −2: 6(−2) − 8
- = −20
2.If f(x) = −x2 − 3x − 1, find f(1).
Answer: −5
- Replace x with 1: −(1)2 − 3(1) − 1
- = −5
3.If f(x) = 2x2 + x − 8, find f(4).
Answer: 28
- Replace x with 4: 2(4)2 + (4) − 8
- = 28
4.If f(x) = −4x, find f(2).
Answer: −8
- Replace x with 2: −4(2)
- = −8
5.If f(x) = 2x2 − 5x + 1, find f(0).
Answer: 1
- Replace x with 0: 2(0)2 − 5(0) + 1
- = 1
6.If f(x) = x2 + 3x + 6, find f(−1).
Answer: 4
- Replace x with −1: (−1)2 + 3(−1) + 6
- = 4
7.If f(x) = 4x2 − 5x, find f(0).
Answer: 0
- Replace x with 0: 4(0)2 − 5(0)
- = 0
8.If f(x) = −3x + 7, find f(0).
Answer: 7
- Replace x with 0: −3(0) + 7
- = 7
9.If f(x) = −6x − 6, find f(−3).
Answer: 12
- Replace x with −3: −6(−3) − 6
- = 12
10.If f(x) = −2x2 − 3x − 9, find f(−2).
Answer: −11
- Replace x with −2: −2(−2)2 − 3(−2) − 9
- = −11
11.If f(x) = 6x − 4, find f(2).
Answer: 8
- Replace x with 2: 6(2) − 4
- = 8
12.If f(x) = −x + 8, find f(3).
Answer: 5
- Replace x with 3: −(3) + 8
- = 5
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