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(1)(-2M+N)2(2)(-2M-N)2(3)(2A+B)2-(2A-B)2

题目详情
(1)(-2M+N)2 (2)(-2M-N)2 (3) (2A+B)2-(2A-B)2
▼优质解答
答案和解析
(-2m+n)²=(-2m)²+2×(-2m)n+n²
=4m²-4mn+n²
(-2m-n)²=(2m+n)²
=(2m)²+2×(2m)n+n²
=4m²+4mn+n²
(2a+b)²-(2a-b)²=[(2a+b)+(2a-b)][(2a+b)-(2a-b)]
=4a×2b
=8ab