早教吧 育儿知识 作业答案 考试题库 百科 知识分享

(-x-y)(x-y)+(x+y)的平方,(2a+b+1)(2a+b-1),165的平方-164x166

题目详情
(-x-y)(x-y)+(x+y)的平方,(2a+b+1)(2a+b-1),165的平方-164x166
▼优质解答
答案和解析
(-x-y)(x-y)+(x+y)²
=-(x+y)(x-y)+(x+y)²
=(x+y)(y-x+x+y)
=2y(x+y)
(2a+b+1)(2a+b-1),
=(2a+b)²-1
165²-164x166
=165²-(165-1)(165+1)
=165²-(165²-1)
=1