Evaluating Algebraic Expressions with Variables

In this video, Mr. J explains how to evaluate expressions with numbers next to variables, which indicates multiplication. He demonstrates this with two examples: 8x and 3xy, using substitution to find the value of the expressions when x equals 9 and y equals 2. The video concludes with tips on representing multiplication in expressions.

What does a number next to a variable typically signify in an algebraic expression?

• Multiplication

• Division

• Subtraction

• Addition

If x equals 9, what is the value of the expression 8x?

• 17

• 9

• 81

• 72

What is the first step in evaluating an expression like 8x when given a specific value for x?

• Substitute the value of x

• Divide by x

• Multiply by x

• Add the values

What symbol is recommended to use between numbers to indicate multiplication?

• Slash (/)

• Dot (.)

• Plus (+)

• None

How should you write the multiplication of 8 and 9 to avoid confusion?

• 8.9

• 8*9

• 89

• 8.9

Why is it important to use a symbol like a dot when writing multiplication between numbers?

• To indicate division

• To prevent confusion with large numbers

• To differentiate from addition

• To look cleaner

In the expression 3xy, if x = 9 and y = 2, what is the final value?

• 6

• 27

• 54

• 18

What does the expression 3xy simplify to when x = 9 and y = 2?

• 54

• 11

• 5

• 27

If you have the expression 3xy and x = 9, y = 2, what should you do first?

• Add x and y

• Substitute the values of x and y

• Divide x by y

• Multiply x by y directly

What final message does the video convey about multiplication with variables?

• It requires addition

• It is complex

• It is straightforward multiplication

• It should be avoided