先化简再求值的题带答案求几道初一先化简再求值的题带答案的,我先自己练练

问题描述:

先化简再求值的题带答案
求几道初一先化简再求值的题带答案的,我先自己练练

①2a-(3a-2b+2)+(3a-4b-1) =( )
=2a-3a+2b-2+3a-4b-1
=(2-3+3)a+(2-4)b+(-2-1)
=2a-2b-3
②5-(1-x)-1-(x-1)=( )
=5-1+x-1-x+1
=4
③2x-(x+3y)-(-x-y)-(x-y)=( )
=2x-x+3y+x+y-x+y
=x+5y