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Ch. 2 - Functions and Graphs
Blitzer - College Algebra 8th Edition
Blitzer8th EditionCollege AlgebraISBN: 9780136970514당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 3

Find f(g(x)) and g (f(x)) and determine whether each pair of functions ƒ and g are inverses of each other. f(x)=3x+8 and g(x) = (x-8)/3

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First, find the composition \( f(g(x)) \) by substituting \( g(x) \) into \( f(x) \). This means replacing every \( x \) in \( f(x) = 3x + 8 \) with \( g(x) = \frac{x - 8}{3} \). So, write \( f(g(x)) = 3 \left( \frac{x - 8}{3} \right) + 8 \).
Next, simplify the expression for \( f(g(x)) \) by performing the multiplication and addition inside the function. Multiply 3 by \( \frac{x - 8}{3} \) and then add 8.
Then, find the composition \( g(f(x)) \) by substituting \( f(x) \) into \( g(x) \). Replace every \( x \) in \( g(x) = \frac{x - 8}{3} \) with \( f(x) = 3x + 8 \). So, write \( g(f(x)) = \frac{(3x + 8) - 8}{3} \).
Simplify the expression for \( g(f(x)) \) by performing the subtraction in the numerator and then dividing by 3.
Finally, determine whether \( f \) and \( g \) are inverses by checking if both compositions \( f(g(x)) \) and \( g(f(x)) \) simplify to \( x \). If both equal \( x \), then \( f \) and \( g \) are inverse functions.

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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

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Function composition involves applying one function to the result of another, denoted as f(g(x)) or g(f(x)). It requires substituting the entire expression of one function into the variable of the other, allowing us to combine functions and analyze their combined effect.
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Algebraic manipulation involves simplifying expressions, substituting variables, and solving equations. It is essential for correctly performing function composition and verifying inverse relationships by simplifying the composed functions to check if they equal x.
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