2. Which of the following pairs of expressions contain like terms? a. xy and x + y b. –8a and a c. a2 and 2a d. cd and dc

Now, I'm not sure what you mean exactly by like terms, but I'll just tell you what I think abouth the equations...

A.   x times y and x plus y

Now, these are different equations, b/c one is multiplying and the other is adding

B.   -8a and a

The first is -8 times a, and the second is just a

C.   a times two and two times a

These are exactly the sam equation, just flipped around

D.   c times d and d times c

These are exactly the same equation, just flipped around

4a. is 3 miles every hour

4b. is 1/3 of an hour per mile

step-by-step explanation: