Year 12 Function Notation, Composites and Inverses Worksheet — Level 1 — Answers
Answer sheet with worked solutions for the Year 12 functions worksheet.
Success TutoringWorksheetsAnswer sheetYear 12 · Mathematics · FunctionsYear 12 Function Notation, Composites and Inverses Worksheet — Level 1 — 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) = −x2 + x + 6, find f(−4).
Answer: −14
- Replace x with −4: −(−4)2 + (−4) + 6
- = −14
2.If f(x) = −3x + 9, find f(3).
Answer: 0
- Replace x with 3: −3(3) + 9
- = 0
3.If f(x) = −3x − 4, find f(5).
Answer: −19
- Replace x with 5: −3(5) − 4
- = −19
4.If f(x) = −x2 − 3x − 1, find f(−4).
Answer: −5
- Replace x with −4: −(−4)2 − 3(−4) − 1
- = −5
5.If f(x) = −2x2 − 6x + 5, find f(−2).
Answer: 9
- Replace x with −2: −2(−2)2 − 6(−2) + 5
- = 9
6.If f(x) = 4x2 − x − 4, find f(2).
Answer: 10
- Replace x with 2: 4(2)2 − (2) − 4
- = 10
7.If f(x) = 5x + 6, find f(−4).
Answer: −14
- Replace x with −4: 5(−4) + 6
- = −14
8.If f(x) = −4x − 7, find f(4).
Answer: −23
- Replace x with 4: −4(4) − 7
- = −23
9.If f(x) = −5x + 3, find f(−4).
Answer: 23
- Replace x with −4: −5(−4) + 3
- = 23
10.If f(x) = 4x − 2, find f(0).
Answer: −2
- Replace x with 0: 4(0) − 2
- = −2
11.If f(x) = 2x, find f(−3).
Answer: −6
- Replace x with −3: 2(−3)
- = −6
12.If f(x) = x2 + 3x + 4, find f(−1).
Answer: 2
- Replace x with −1: (−1)2 + 3(−1) + 4
- = 2
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