10th Grade Function Notation, Composites and Inverses Worksheet — Level 2 — Practice Set 4 — Answers
Answer sheet with worked solutions for the 10th Grade functions worksheet.
Success TutoringWorksheetsAnswer sheet10th Grade · Mathematics · Functions10th Grade Function Notation, Composites and Inverses Worksheet — Level 2 — 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) = −2x2 + 4x + 7, find f(5).
Answer: −23
- Replace x with 5: −2(5)2 + 4(5) + 7
- = −23
2.If f(x) = −2x2 + 5x − 2, find f(−4).
Answer: −54
- Replace x with −4: −2(−4)2 + 5(−4) − 2
- = −54
3.f(x) = −2x + 3 and g(x) = 2x + 4. Find g(f(x)) in simplest form.
Answer: −4x + 10
- g(f(x)) = 2(−2x + 3) + 4
- = −4x + 10
4.If f(x) = 4x2 + 3x − 2, find f(−3).
Answer: 25
- Replace x with −3: 4(−3)2 + 3(−3) − 2
- = 25
5.f(x) = 2x and g(x) = 3x + 2. Find f(g(x)) in simplest form.
Answer: 6x + 4
- f(g(x)) = 2(3x + 2)
- = 6x + 4
6.If f(x) = −3x2 + 5x + 4, find f(4).
Answer: −24
- Replace x with 4: −3(4)2 + 5(4) + 4
- = −24
7.f(x) = x and g(x) = −2x − 5. Find g(f(x)) in simplest form.
Answer: −2x − 5
- g(f(x)) = −2(x) − 5
- = −2x − 5
8.f(x) = −3x + 1 and g(x) = x + 6. Find g(f(x)) in simplest form.
Answer: −3x + 7
- g(f(x)) = 1(−3x + 1) + 6
- = −3x + 7
9.f(x) = −2x − 6 and g(x) = 2x − 2. Find f(g(x)) in simplest form.
Answer: −4x − 2
- f(g(x)) = −2(2x − 2) − 6
- = −4x − 2
10.If f(x) = −3x2 + x − 1, find f(−2).
Answer: −15
- Replace x with −2: −3(−2)2 + (−2) − 1
- = −15
11.f(x) = 5x − 3 and g(x) = 3x − 2. Find g(f(x)) in simplest form.
Answer: 15x − 11
- g(f(x)) = 3(5x − 3) − 2
- = 15x − 11
12.If f(x) = −2x2 − x − 8, find f(5).
Answer: −63
- Replace x with 5: −2(5)2 − (5) − 8
- = −63
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