Let f and g be defined by the following table: Find
Ch. 2 - Functions and Graphs

Chapter 3, Problem 95
Find all values of x satisfying the given conditions. f(x) = 2x − 5, g(x) = x² − 3x + 8, and (ƒ o g) (x) = 7.
Verified step by step guidance1
Understand that the composition (ƒ o g)(x) means ƒ(g(x)), which is the function ƒ applied to the output of g(x).
Write the composition explicitly: (ƒ o g)(x) = ƒ(g(x)) = 2(g(x)) - 5.
Substitute g(x) = x² - 3x + 8 into the expression: 2(x² - 3x + 8) - 5.
Set the expression equal to 7 as given: 2(x² - 3x + 8) - 5 = 7.
Solve the resulting quadratic equation by first expanding, then simplifying, and finally using factoring or the quadratic formula to find all values of x.

Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
6mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Function Composition
Function composition involves applying one function to the result of another, denoted as (f o g)(x) = f(g(x)). It means you first evaluate g(x), then substitute that result into f. Understanding this process is essential to correctly set up and solve equations involving composed functions.
Recommended video:
Function Composition
Quadratic Functions
A quadratic function is a polynomial of degree two, typically written as ax² + bx + c. Recognizing the form and properties of quadratics helps in evaluating g(x) and simplifying expressions. Quadratic functions often require factoring or using the quadratic formula to find roots.
Recommended video:
Solving Quadratic Equations Using The Quadratic Formula
Solving Equations
Solving equations involves finding all values of the variable that satisfy the given equality. In this problem, after composing the functions, you will get an equation to solve for x, which may be linear or quadratic. Techniques include isolating variables, factoring, or applying the quadratic formula.
Recommended video:
Solving Logarithmic Equations
Related Practice
Textbook Question
7
views
Textbook Question
The functions in Exercises 93–95 are all one-to-one. For each function, (a) find an equation for f^(-1)x, the inverse function. (b) Verify that your equation is correct by showing that f(f^(-1)(x)) = x and f^(-1)(f(x)) = x. f(x) = (x - 7)/(x + 2)
1
views
Textbook Question
In Exercises 95–96, let f and g be defined by the following table: Find |ƒ(1) − f(0)| − [g (1)]² +g(1) ÷ ƒ(−1) · g (2) .
Textbook Question
Let f(x) = x² − x + 4 and g(x) = 3x – 5. Find g(-1) and f(g(-1)).
Textbook Question
Determine whether each statement is true or false. If the statement is false, make the necessary change(s) to produce a true statement.
If and , find and .
Textbook Question
Begin by graphing the standard cubic function, f(x) = x³. Then use transformations of this graph to graph the given function. g(x) = x³-3
4
views
