1) -16ab+59m+76ab-37m+34ab=94ab+22m
2)23xy-15x+37xy-19xy-9x=41xy-26x
3)5/6xy+4/5x-7/12xy-8/15x=3/12xy+4/15x
4)4mn+5bc-7mn+13bc-6bc=12bc-3mn
5)(3x-7xy+5y)+(4x+5xy-3y)=3x-7xy+5y+4x+5xy-3y=7x-2xy+2y
6)(4x+7xy-2y)-(7x-4xy-3y)=4x+7xy-2y-7x+4xy+3y=y+11xy-3x