Answers

2016-06-27T19:35:26+08:00
Addition:
Add the similar terms just the same as how you add integers.
Like signs - add them and copy the sign; unlike signs - subtract them and copy the sign of the one having the greater absolute value.
                          
  ab  -4a  +3b
                          
2ab  -6a   -8b
+                          -ab  + a            +3
=                         2ab - 9a - 5b  + 3

Subtraction
Subtract the similar terms just the same as how you subtract integers. Change the operation (to addition) and the sign/s of the subtrahend.
                        
30x²y    -15xy    +6y
+                      -25x²y    +9xy     +7y
=                         5x²y    -6xy     +13y

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