I am giving just answers,you just try them and see if you get them right

1. 17a+12b+9a+20b = 26a +32b

2. 5c+d+8c+4d =13c+5d

4. 7b + 8x - 3b + x + b = 5b +9x

5. 3a - 5b + 9b + 6a + c = 9a+4b +c

i worked all the problems and theae are the once I could not do

Please do try your homework problems yourseff first and let me know where you are having problem

Here is te solution of one

15t + 6t-9t

15t+6t-9t = 12t