Combine like terms. 9 + 3x – 9x + 16
a. 18x + 3x + 16
b. 19x
c. 25 – 6x
d. 3x + 16

9 + 3x - 9x + 16
Like terms are terms that have the same variable and powers.

9 and 16 are like terms. They don't have any other variables and can easily be solved.

9 + 16 = 25

3x and -9x are like term. They both have the same variable and powers, x. The coefficients, 3 an d-9, don't have to match as long as the variable and powers are the same.

3x - 9x = -6x

9 + 3x - 9x + 16 ⇒ 25 - 6x Choice C.