(1+0.34+0.45+0.56)*(0.34+0.45+0.56+0.67)-(1+0.34+0.56+0.45+0.67)*(0.34+0.45+0.56)
问题描述:
(1+0.34+0.45+0.56)*(0.34+0.45+0.56+0.67)-(1+0.34+0.56+0.45+0.67)*(0.34+0.45+0.56)
时间只有1个小时了,求求啊.
答
令a=0.34+0.45+0.56
原式=(1+a)(a+0.67)-(1+a+0.67)a
=(1+a)a+0.67(1+a)-(1+a)a-0.67a
=0.67(1+a)-0.67a
=0.67+0.67a-0.67a
=0.67