Variables and Expressions Review

A variable is:

• A fixed value

• A value that can change

• A type of function

• A mathematical operation

You can add or subtract monomials with the same variables because:

• they have the same variable parts and can be combined like terms.

• they have different exponents.

• they are always constants.

• they cannot be combined.

Simplify: 9a + 4b - 5a + 7b - 2a

• 2a + 11b

• 2a + 9b

• a + 11b

• 2a + b

Simplify: 12x - 3y + 5z - 4x + 2y - z

• 8x - y + 4z

• 16x - 5y + 6z

• 8x - 5y + 4z

• 8x - y + 6z

Simplify: 5p + 8q - 3p - q + 6p - 4q

• 8p + 3q

• 14p + 13q

• 5p + 3q

• 8p + 7q

Simplify: 10m - 2n + 6m + 5n - m - 3n

• 15m

• 15n

• 9m + 0n

• 16m - n

Simplify: 7r + 6s - 4r - 2s + 9r - 5s

• 12r - s

• 20r + 9s

• 2r + 9s

• 16r - 13s

Evaluate: 25 - 3y + 4.5, when y = 6

• 7.5

• 10.5

• -2.5

• 15.5

Evaluate the following expression: 4x/2 + 7, when x = 10.

• 27

• 17

• 47

• 23

Evaluate the following expression: 6a + 5b - 2a, when a = 3 and b = 8.