问题
选择题
将2(x+y)-3(x-y)-4(x+y)+5(x-y)-3(x-y)合并同类项得( )
A.-3x-y
B.-2(x+y)
C.-x+y
D.-2(x+y)-(x-y)
答案
原式=2(x+y)-4(x+y)-3(x-y)+5(x-y)-3(x-y)
=-2(x+y)-(x-y)
=-2x-2y-x+y
=-3x-y,
故选A.
将2(x+y)-3(x-y)-4(x+y)+5(x-y)-3(x-y)合并同类项得( )
A.-3x-y
B.-2(x+y)
C.-x+y
D.-2(x+y)-(x-y)
原式=2(x+y)-4(x+y)-3(x-y)+5(x-y)-3(x-y)
=-2(x+y)-(x-y)
=-2x-2y-x+y
=-3x-y,
故选A.