Year 12 Function Notation, Composites and Inverses Worksheet — Level 1 — Practice Set 4 — 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 — 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) = −3x2 − x − 5, find f(2).
Answer: −19
- Replace x with 2: −3(2)2 − (2) − 5
- = −19
2.If f(x) = 2x2 − 2x − 4, find f(−1).
Answer: 0
- Replace x with −1: 2(−1)2 − 2(−1) − 4
- = 0
3.If f(x) = −4x + 6, find f(−2).
Answer: 14
- Replace x with −2: −4(−2) + 6
- = 14
4.If f(x) = −6x + 8, find f(5).
Answer: −22
- Replace x with 5: −6(5) + 8
- = −22
5.If f(x) = −3x2 − 6x − 8, find f(−3).
Answer: −17
- Replace x with −3: −3(−3)2 − 6(−3) − 8
- = −17
6.If f(x) = 3x2 − x − 2, find f(3).
Answer: 22
- Replace x with 3: 3(3)2 − (3) − 2
- = 22
7.If f(x) = x2 + 4x + 8, find f(4).
Answer: 40
- Replace x with 4: (4)2 + 4(4) + 8
- = 40
8.If f(x) = 2x2 − 5x + 3, find f(−4).
Answer: 55
- Replace x with −4: 2(−4)2 − 5(−4) + 3
- = 55
9.If f(x) = −5x + 3, find f(2).
Answer: −7
- Replace x with 2: −5(2) + 3
- = −7
10.If f(x) = −x − 2, find f(−2).
Answer: 0
- Replace x with −2: −(−2) − 2
- = 0
11.If f(x) = 3x2 − 6x + 9, find f(−4).
Answer: 81
- Replace x with −4: 3(−4)2 − 6(−4) + 9
- = 81
12.If f(x) = −4x − 9, find f(4).
Answer: −25
- Replace x with 4: −4(4) − 9
- = −25
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