Problem 60 - Algebra 2

Question

Let \(g(x)=3 x+2\) and \(f(x)=\frac{x-2}{3} .\) Find each value. $$ f(g(0)) $$

Step-by-Step Solution

Answer

The value of \( f(g(0)) \) is 0.

Step 1: Find g(0)

To find \( g(0) \), replace \( x \) with 0 in the function \( g(x) \). This gives \( g(0) = 3 \cdot 0 + 2 = 2 \).

Step 2: Substitute g(0) into f(x)

Now that we have found \( g(0) = 2 \), we need to find \( f(g(0)) \), which means to find \( f(2) \). To do this, substitute \( x \) with 2 in the function \( f(x) \). This gives \( f(2) = \frac{2-2}{3} = 0 \).

Step 3: Combine the results

At this point, we have found that \( f(g(0)) = f(2) = 0 \), which means that composing the function \( g \) followed by the function \( f \) and using 0 as the input gives a final output of 0.

Key Concepts

Understanding Linear Functions

Linear functions are one of the building blocks of algebra. They take the form \( g(x) = ax + b \), where \( a \) and \( b \) are constants. For example, in the function \( g(x) = 3x + 2 \), \( 3 \) is the slope and \( 2 \) is the y-intercept. The slope indicates how steep the line is, while the y-intercept is the point where the line crosses the y-axis.
These functions graph as straight lines, hence the name "linear." Each input \( x \) is mapped to one and only one output \( g(x) \). Linear functions are straightforward, and their predictability makes them useful in various real-world applications.
Let's explore how linear functions play a critical role when we compose them with other functions, leading us to complex problem-solving strategies.

Exploring Inverse Functions

Inverse functions are fascinating because they essentially "reverse" the effect of the original function. For a function to have an inverse, each output must be paired with exactly one input. It's like undoing the steps of the original function.
Consider the function \( f(x) = \frac{x-2}{3} \), which can be seen as an inverse of \( g(x) = 3x + 2 \). When you compose a function with its inverse, you get back to your original value.

• If you apply \( g \) and then \( f \), like in \( f(g(x)) \), you should end up with \( x \) again, given that both functions are perfectly inverse.
• This relationship shows how inverse functions help in restoring original states, making them indispensable in algebraic settings and real-world scenarios alike.

Understanding this principle provides insight into how functions can be manipulated and utilized effectively.

Delving into Algebraic Manipulation

Algebraic manipulation involves rearranging expressions or equations to reveal new insights or solutions. It requires a strong understanding of algebraic principles and the ability to think flexibly about numbers and variables.
In the problem \( f(g(0)) \), we replace \( x \) with 0 in \( g(x) = 3x + 2 \) to find \( g(0) \). Next, we substitute this result into \( f(x) \). Such steps demonstrate how algebraic manipulation allows for the computation of specific values through function composition.

• The ability to substitute values and solve expressions is an essential skill in mathematics.
• Learning to manipulate functions provides the toolkit for tackling more complex equations and models.

Ultimately, these techniques pave the way for solving a diverse range of mathematical problems, offering a systematic approach to exploring mathematical relationships.