早教吧 育儿知识 作业答案 考试题库 百科 知识分享

将下(n+y)-a(n-y)-4(n+y)+5(n-y)-a(n-y)合并同类项得()A.-3x-yB.-2(x+y)C.-x+yD.-2(x+y)-(x-y)

题目详情
将下(n+y)-a(n-y)-4(n+y)+5(n-y)-a(n-y)合并同类项得(  )

A.-3x-y
B.-2(x+y)
C.-x+y
D.-2(x+y)-(x-y)
▼优质解答
答案和解析
原式=2(x+y)-j(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.