Simplify 9a + b + a + 2b

First you have to combine your like terms both 9a and a are like terms add them an you get 10a. Secondly combine your oyher like terms b and 2b add them and you get 3b so. 10a + 3b

9a+b+a+2b

Put the a together and the b together.

10a+3b

And there's your answer