Answer:
2a + 4 + 7b
Explanation:
ohh so to do this umm if you want it to be easier you can put a different symbols under the ones with the same variable. like a dot under 4a and - 2a, a square under .....
but if you want to do it without that, all you have to do is add them like numbers
you can also move them closer to each other. for example:
4a - 2a + 8 - 4 + 7b
4 - 2 is 2 so you just have to write 2a
2a + 8 - 4 + 7b
simplify
2a + 4 + 7b
since there are no other numbers with the variable b the equation above is the answer