11th Grade Function Notation, Composites and Inverses Worksheet — Level 2 — Practice Set 2 — Answers
Answer sheet with worked solutions for the 11th Grade functions worksheet.
Success TutoringWorksheetsAnswer sheet11th Grade · Mathematics · Functions11th Grade Function Notation, Composites and Inverses Worksheet — Level 2 — Practice Set 2 — 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 + 6x − 9, find f(3).
Answer: −18
- Replace x with 3: −3(3)2 + 6(3) − 9
- = −18
2.If f(x) = x2 + 4x + 5, find f(5).
Answer: 50
- Replace x with 5: (5)2 + 4(5) + 5
- = 50
3.If f(x) = −3x2 + 3x + 5, find f(−2).
Answer: −13
- Replace x with −2: −3(−2)2 + 3(−2) + 5
- = −13
4.If f(x) = x2 − 3, find f(4).
Answer: 13
- Replace x with 4: (4)2 − 3
- = 13
5.f(x) = 2x − 4 and g(x) = 5x + 6. Find f(g(x)) in simplest form.
Answer: 10x + 8
- f(g(x)) = 2(5x + 6) − 4
- = 10x + 8
6.f(x) = x + 4 and g(x) = 5x − 3. Find g(f(x)) in simplest form.
Answer: 5x + 17
- g(f(x)) = 5(x + 4) − 3
- = 5x + 17
7.If f(x) = 3x2 + x + 9, find f(0).
Answer: 9
- Replace x with 0: 3(0)2 + (0) + 9
- = 9
8.If f(x) = −x2 + 4x − 4, find f(−1).
Answer: −9
- Replace x with −1: −(−1)2 + 4(−1) − 4
- = −9
9.If f(x) = 4x2 + x − 6, find f(0).
Answer: −6
- Replace x with 0: 4(0)2 + (0) − 6
- = −6
10.f(x) = 2x + 5 and g(x) = 4x + 2. Find f(g(x)) in simplest form.
Answer: 8x + 9
- f(g(x)) = 2(4x + 2) + 5
- = 8x + 9
11.f(x) = 5x + 5 and g(x) = −4x + 1. Find f(g(x)) in simplest form.
Answer: −20x + 10
- f(g(x)) = 5(−4x + 1) + 5
- = −20x + 10
12.f(x) = 5x + 4 and g(x) = x + 3. Find f(g(x)) in simplest form.
Answer: 5x + 19
- f(g(x)) = 5(x + 3) + 4
- = 5x + 19
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