4r + 9r - 11r + 7r

Simfly the expressions by combing like terms?

Solve this one in exactly the same way as I solved the one

that you posted 1 minute before this one.

- - add up all the ' r 's.

- - add up all of the just-plain-numbers

This time, the answer looks like 9r.

You should spend a few minutes with it so that

you know where this answer comes from.

9r because 4+9 is 13+7 is 20-11 is 9