Functions Practice Problems & Exercises - 7th Grade Math

Master function concepts with step-by-step practice problems. Learn to evaluate functions, identify domains, and understand function notation through interactive exercises.

📚Master Functions with Interactive Practice Problems
  • Evaluate functions by substituting numerical values for variables
  • Identify independent and dependent variables in real-world scenarios
  • Graph linear functions using coordinate points and function notation
  • Determine function domains and understand one-to-one relationships
  • Convert between algebraic, graphical, and tabular function representations
  • Solve problems involving function slopes and rates of change

Understanding Functions

Complete explanation with examples

On one hand, functions are a fairly abstract concept, but on the other hand, they are very useful in many areas of mathematics. The topic of functions dominates many fields, including algebra, trigonometry, differential and integral calculus, and more. Therefore, it's important to understand the concept of functions, so that it can be applied in any of the fields of mathematics, and especially when we start learning about functions in seventh grade.

A function expresses a relationship between two variables (X and Y)

What is a function?

A function expresses a relationship between two variables (X and Y)

  • X X represents an independent variable 
  • Y Y represents a dependent variable

An independent variable (X) (X) is a non-variable constant by which we explain (Y) (Y) , the dependent variable

For example, if Daniela worked as a babysitter and earned 30 dollars per hour and we want to know how much Daniela made after 10 10 hours, the number of hours worked is actually the independent variable (X) (X) with which we know how much she earned. Ultimately this is the dependent variable. (Y) (Y)

In other words, it can be said that the amount Daniela earned is a function of the number of hours she worked (X) (X) .
We will mark the data of the function algebraically in this way: fx=X×30 fx=X\times30

It's important to remember that each element in the domain X X will always have only one element in the range Y Y .
This means that it's not possible that during the 10 10 hours Daniela worked, she received both 300 300 dollars and 200 200 dollars.


Detailed explanation

Practice Functions

Test your knowledge with 17 quizzes

Determine which domain corresponds to the function described below:

The function represents the amount of fuel in a car's tank according to the distance traveled by the car.

Examples with solutions for Functions

Step-by-step solutions included
Exercise #1

Is the function in the graph decreasing? yx

Step-by-Step Solution

To solve this problem, we'll follow these steps:

  • Step 1: Verify the graph's overall path direction
  • Step 2: Confirm if the y-values are decreasing as we proceed from the left side of the graph to the right side (increasing x-values).

Now, let's work through each step:

Step 1: By examining the graph, the red line starts at a higher point on the y-axis and moves downward to a lower point as it moves horizontally across the x-axis from left to right.

Step 2: Since for every point, the red line descends as it progresses from the leftmost point to the rightmost, this indicates a consistent decrease in the y-values.

Therefore, the solution to the problem is Yes, the function in the graph is decreasing.

Answer:

Yes

Exercise #2

Is the function in the graph decreasing?

yx

Step-by-Step Solution

To analyze whether the function in the graph is decreasing, we must understand how the function's behavior is defined by its graph:

  • Step 1: Examine the graph. The graph presented is a horizontal line.
  • Step 2: Recognize the properties of a horizontal line. Horizontally aligned lines correspond to constant functions because the y y -value remains the same for all x x -values.
  • Step 3: Define the criteria for a function to be decreasing. A function decreases when, as x x increases, the value of f(x) f(x) decreases.
  • Step 4: Apply this criterion to the horizontal line. Since the y y -value is constant and does not decrease as x x moves rightward, the function is not decreasing.

Therefore, the function represented by the graph is not decreasing.

Answer:

No

Exercise #3

Is the function in the graph below decreasing?

yx

Step-by-Step Solution

To determine if the function is decreasing, we will analyze the graph visually:

The graph shows a line connecting from the bottom-left to the top-right of the graph area, indicating the line has a positive slope. This type of graph indicates the function is increasing, not decreasing.

A decreasing function means its value goes down as x x increases, which is equivalent to having a negative slope.

Since the graph appears with a positive slope, the function is not decreasing.

Thus, the correct choice to the problem, which asks if the function in the graph is decreasing, is No.

Answer:

No

Exercise #4

Does the function in the graph decrease throughout?

YYYXXX

Step-by-Step Solution

To solve this problem, we'll begin by examining the graph of the function provided:

  • Step 1: Observe the graph from left to right along the x-axis.
  • Step 2: Look for any intervals where the function value (y-coordinate) does not decrease as the x-value increases.
  • Step 3: Pay special attention to segments where the graph might look horizontal or rising.

Upon inspecting the graph, we find:

- There are sections where the function's y-values appear to remain constant or potentially rise as the x-values increase. Specifically, even if the function decreases in major portions, any interval where it doesn't means the function cannot be classified as decreasing throughout.

Thus, the function does not strictly decrease on the entire interval shown. Therefore, the solution to the problem is No.

Answer:

No

Exercise #5

Is the function shown in the graph below decreasing?

yx

Step-by-Step Solution

The graph presented is a straight line. To determine whether the function is decreasing, we need to examine the slope of this line.

The line has a negative slope, as it moves downward from left to right. A function is considered decreasing when its slope is negative.

In formal terms, for a linear function expressed as y=mx+c y = mx + c , if the slope m m is negative, the function is decreasing over its entire domain.

From the graph, it's evident that the line has a negative slope, thus indicating that the function is indeed decreasing.

Therefore, the answer to the problem is Yes.

Answer:

Yes

Frequently Asked Questions

What is a function in simple terms for 7th grade?

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A function is a mathematical relationship between two variables where each input (x-value) has exactly one output (y-value). Think of it like a machine: you put in a number, follow a rule, and get out exactly one result.

How do you evaluate a function step by step?

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To evaluate a function: 1) Replace the variable (usually x) with the given number, 2) Follow the order of operations to calculate, 3) Simplify to get your final answer. For example, if f(x) = 2x + 5 and x = 3, then f(3) = 2(3) + 5 = 11.

What's the difference between independent and dependent variables?

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The independent variable (x) is the input you control or choose. The dependent variable (y) is the output that depends on your input. In Daniela's babysitting example, hours worked is independent, and money earned is dependent.

Why can each x-value have only one y-value in a function?

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This is the fundamental rule of functions - each input must have exactly one output. If one x-value could produce multiple y-values, it wouldn't be a function. This ensures predictable, consistent relationships.

How do you find the domain of a function?

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The domain includes all possible x-values you can substitute into a function without causing mathematical errors. For most basic functions, the domain is all real numbers, but watch out for divisions by zero or square roots of negative numbers.

What are the main ways to represent functions?

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Functions can be represented in four main ways: 1) Algebraically (equations like f(x) = 2x + 1), 2) Graphically (on coordinate planes), 3) In tables (x and y value pairs), 4) Verbally (word descriptions of relationships).

How do you graph a linear function?

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To graph a linear function: 1) Choose at least two x-values, 2) Calculate corresponding y-values using the function, 3) Plot these coordinate points, 4) Draw a straight line through the points. The slope tells you how steep the line is.

What makes a function linear versus other types?

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A linear function has the variable raised only to the first power (no squares, cubes, etc.) and graphs as a straight line. Examples include f(x) = 2x + 3 or y = -x + 5. Quadratic functions have x², while polynomial functions have higher powers.

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