Substituting Values for Variables

This lesson covers evaluating algebraic expressions by substituting values for variables. It begins with simple expressions and progresses to more complex ones involving multiple variables and exponents. The importance of following the order of operations is emphasized throughout. Examples include evaluating expressions like 3x-2, 4y+5y, 30x-15y, and 4x^2+5y^3 with specific values for variables. The lesson concludes with a reminder to substitute, perform operations, and simplify.

What is the result of evaluating the expression 3x - 2 when x is replaced with 5?

• 15

• 17

• 11

• 13

If y is substituted with 8 in the expression 4y + 5y, what is the final result?

• 88

• 80

• 72

• 64

How do you evaluate the expression 30x - 15y when x is 2 and y is 3?

• 10

• 15

• 20

• 25

What is the value of 4x^2 + 5y^3 when x is 3 and y is 2?

• 80

• 72

• 64

• 76

Which operation should be performed first when evaluating 4x^2 + 5y^3?

• Substitution

• Exponents

• Multiplication

• Addition