Evaluating Expressions with Variables

The video tutorial demonstrates how to evaluate algebraic expressions by substituting variables with given values. It covers three examples: evaluating 3x + 1 for x = 5, 3x + 1 for x = -2, and a^2 - a for a = 6. The process involves replacing the variable with the specified number and performing arithmetic operations to find the result.

What is the first step in evaluating an expression when a specific value is given for a variable?

• Divide the expression by the value

• Substitute the value for the variable

• Multiply the value by the expression

• Add the value to the expression

If x equals 5, what is the result of 3x + 1?

• 16

• 17

• 15

• 14

What operation is performed after substituting x with 5 in the expression 3x + 1?

• Addition

• Multiplication

• Division

• Subtraction

When x is -2, what is the value of 3x + 1?

• -7

• -5

• -3

• -1

What is the result of 3 times -2 in the expression 3x + 1?

• -8

• -6

• -4

• -2

What is the final step in evaluating 3x + 1 when x is -2?

• Add 1 to -6

• Divide -6 by 1

• Multiply -6 by 1

• Subtract 1 from -6

What is the expression a squared minus a when a equals 6?

• 28

• 32

• 30

• 34

What is the value of 6 squared in the expression a squared minus a?

• 30

• 32

• 34

• 36

What is the result of subtracting 6 from 36 in the expression a squared minus a?

• 28

• 34

• 30

• 32

Which of the following is true about variables in expressions?

• Variables cannot be negative

• Variables must always be x

• Variables can be any symbol

• Variables must be numbers