Writing algebraic equations

What is the difference between an expression and equation?

• Expressions have an equal sign and equations do not have an equal sign

• Expressions do not have an equal sign and equations do have an equal sign

• There is not a difference

• Expressions do not have variables and equations have variables

What is a variable?

• A number that represents an unknown value

• A letter that represents an unknown value

Which choice models this situation?

At Pierce County Middle School, there are 5 art classes with 24 students in each class. How many students altogether are in the art classes?

• s - 5 = 24

• s + 5 = 24

• 5s = 24

• s/5 = 24

What equation is modeled?

• 2x = -4

• 2x = 4

• 2+x = 4

• x+2=4

If chocolate chip cookies cost $3.00 per cookie plus $2 for boxing them up in a decorated box, what would the expression be?

• 3 + 2x

• 3x + 2

• 3x + 2x

• 5x

What could this represent? 7x + 2 = 30

• Buying pet turtles for $7 each plus two cans of turtle food cost $30.

• Seven bags of candy plus 2 extra snickers bars equals 30 dollars.

• Two yoyos plus seven frisbees is thirty cents.

• Buying seven calculators plus $2 per bundle of pencils is $30.

Bob's Plumbing charges $15 per hour plus a service fee of $40 for coming out to your house. Which equation models this situation?

• y = 15x + 40

• y = 40x + 15

• y = 15x

• y = 15x - 40

Dexter's Gym charges a one-time registration fee of $40 and $20 each month. The total fee after x months is $340. Which equation models this situation?

• 40x + 20 = 340

• 20x + 40 = 340

• 20x - 40 = 340

• 20 + 340 = 40x

Scott's Automotive charges $35 for each car plus $7 per hour. Write an equation that represents this scenario if Kylie was charged $63.

• 35x + 7 = 63

• 7x = 63

• 7x - 35 = 63

• 7x + 35 = 63

A holiday meal cost $12.50 a person plus a delivery fee of $30. Which equation represents the amount a holiday meal costs(y), including delivery, for x people?

• y = 12.50 + 30x

• y = 30 + 12.50x

• y = 12.50 + 30

• 12.50x = 30