Equations With Variables

In the equation 2x + 3y = 19, what is/are the variable(s)? Choose the best answer.

• x

• y

• =

• Both x and y are variables

What branch of mathematics deals with equations with variables?

• Algebra

• Geometry

• Calculus

• Physics

What is a variable?

• It's a number equation.

• A letter representing an unknown number in an equation.

• The symbols in an equation that aren't letters or numbers.

• Any equation with an equals sign.

How do we figure out the value of a variable?

• Add up all the numbers in the equation.

• Multiply the variable by itself.

• Isolate the variable on one side of the equals sign.

• A variable has no set value.

Amy wants to buy soda AND pizza for her Halloween party. She has $45 to spend. One case of soda costs $4, and one pizza costs $8. Write an equation that could be used to find a valid combination for as many cases of soda, x, and pizzas, y, as she can afford.

• 8x + 4y = 45

• 4x - 8y = 45

• 12xy = 45

• 4x + 8y = 45

Felicia is buying shirts for her baseball team. She will pay $9.30 for each shirt plus a one-time fee of $25.50 for the design.

Which equation can be used to find y , the total cost to buy x shirts?

• y=9.3x+25.5

• y =25.5x+9.3

• y=9.3x-25.5

• y=25.5x-9.3

Felicia is buying shirts for her baseball team. She will pay $9.30 for each shirt plus a one-time fee of $25.50 for the design. Which equation can be used to find y, the total cost to buy x shirts?

• y=9.3x+25.5

• y =25.5x+9.3

• y=9.3x-25.5

• y=25.5x-9.3

How would you solve the equation 4x = 100?

• Divide 100 by 4

• Subtract 4 from 100

• Add 4 to 100

• Multiply 100 by 4

In the equation 2x + 3y = 19, what is the constant?

• y

• 19

• x

• 2

Solve for x: 7x + 7 = 21

• x = 7

• x = 4

• x = 3

• x = 2