早教吧 育儿知识 作业答案 考试题库 百科 知识分享

若把x-y看成一项,合并2(x-y)2+3(x-y)+5(y-x)2+3(y-x)得()A.7(x-y)2B.-3(x-y)2C.-3(x+y)2+6(x-y)D.(y-x)2

题目详情
若把x-y看成一项,合并2(x-y)2+3(x-y)+5(y-x)2+3(y-x)得(  )
A. 7(x-y)2
B. -3(x-y)2
C. -3(x+y)2+6(x-y)
D. (y-x)2
▼优质解答
答案和解析
2(x-y)2+3(x-y)+5(y-x)2+3(y-x),
=[2(x-y)2+5(y-x)2]+[3(y-x)+3(x-y)],
=7(x-y)2
故选A.