To simply to expression 6ab+3ab-7ab, we do: 6ab+3ab-7ab+= (Just do regular addition and subtraction if they have the same coefficent) 9ab-7ab= 2ab So the answer is C.
Simplifying 6ab + 3ab - 7ab so we can write it 6ab + 3ab - 7ab = 0 ( because there is nothing on right side ) 9ab - 7ab = 0 2ab = 0 So the coefficient of ab is 2.
