VALUE OF A VARIABLE

Value Of A Variable

Definition Of Value Of A Variable

A numerical quantity assigned to a variable is called its value.

More About Value of a Variable

Solving or evaluating the equation or expression can determine the value of a variable.

Example of Value of a Variable

Let us find the value of y of the equation y = 2x - 3, where x = 4.
y = 2x - 3 = 2(4) - 3 = 8 - 3 = 5, therefore, the value of y is 5.

Video Examples: How to find the value of a variable

Solved Example on Value of a Variable

Ques: Find the value of the variable y in the equation 16 + y = - 41

Choices:

A. - 57
B. 59
C. 57
D. 69
Correct Answer: A

Solution:

Step 1: 16 + y = - 41 [Original equation.]
Step 2: 16 + y - 16 = - 41 - 16 [Subtract 16 from each side.]
Step 3: y = - (41 + 16) [Use associative property of addition.]
Step 4: y = - 57 [Add inside the grouping symbols.]

Quick Summary

The value of a variable is found by solving or evaluating an equation or expression.
Substitution is used to find the value when given other variable values.

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⚠️ Common Mistakes

Incorrect arithmetic operations when solving for the variable.
Forgetting to apply the correct order of operations.
Not substituting the correct value for the variable.

🌍 Real-World Uses

Calculating the total cost of items where 'x' is the number of items and 'y' is the total cost: value of the variable 'x' determines the total cost 'y'.
Determining the distance traveled by a car where 't' is the time traveled and 'd' is the distance: value of the variable 't' influences the distance 'd'.
Finding the area of a rectangle where 'l' is the length and 'w' is the width and 'A' is the area: the values of 'l' and 'w' determine the area A.

📋 Standards Alignment

CCSS.MATH.CONTENT.6.EE.B.5
CCSS.MATH.CONTENT.7.EE.B.4

🍎 Teacher Insights

Emphasize the importance of showing each step when solving for a variable to avoid errors. Provide various examples and practice problems to reinforce the concept.

🎓 Prerequisites

Basic Arithmetic
Understanding of Variables

Check Your Knowledge

Q1: What is the value of y in the equation y = 3x + 2 when x = 2?

A. 4 B. 6 C. 8 D. 10

Q2: Solve for y: 16 + y = -41

A. -57 B. 59 C. 57 D. 69

Frequently Asked Questions

Q: How do I find the value of a variable in an equation?
A: Isolate the variable on one side of the equation by performing inverse operations on both sides.

Q: What does it mean to evaluate an expression for a given variable value?
A: It means to substitute the given value for the variable and simplify the expression using the order of operations.