Evaluating Expressions with Variables

This video tutorial by Mr. J covers a mini-course on evaluating mathematical expressions. It includes sections on expressions with one and two variables, numbers next to variables, variables next to variables, expressions with exponents, and expressions in fractional form. Each section provides examples and uses substitution and order of operations to find the value of expressions. The video is structured with chapters and timestamps for easy navigation.

What is the first step in evaluating an expression with a variable?

• Multiply all terms

• Divide the expression by 2

• Substitute the variable with its given value

• Add all numbers first

When evaluating 8x with x = 5, what is the result?

• 13

• 40

• 85

• 45

In the expression 7B - A, if B = 9 and A = 10, what is the value?

• 70

• 19

• 63

• 53

What operation is performed first in the expression 42/G + 8H when G = 7 and H = 5?

• Multiplication

• Division

• Addition

• Subtraction

How do you represent multiplication when substituting values into an expression?

• Using a plus sign

• Using a dot or asterisk

• By placing numbers side by side

• Using a division sign

What is the result of 3xy when x = 9 and y = 2?

• 72

• 18

• 27

• 54

In the expression x^2, what does the exponent indicate?

• Multiply x by itself

• Divide x by 2

• Subtract 2 from x

• Add x to itself

What is the value of 4x^2 when x = 3?

• 27

• 9

• 12

• 36

How do you evaluate a fractional expression like 6x/(x-3) when x = 6?

• Divide the numerator by the denominator

• Subtract the denominator from the numerator

• Add the numerator and denominator

• Multiply the numerator and denominator

What is the result of y^2 - 20 over x + y when x = 6 and y = 10?

• 10

• 15

• 5

• 20