扣扣同步助手官网:1-2×51+51×51,利用乘法公式

来源:百度文库 编辑:中科新闻网 时间:2024/05/01 23:16:12

1-2*51+51*51
=1+51*(-2+51)
=1+51*49
=1+(50+1)*(50-1)
=1+50*50-1*1
=2500

1-2*51+51*51
=1+51*(51-2)
=1+51*49
=1+(50+1)*(50-1)
=1+50*50-1
=2500

=1+(51-2)*51=1+(50-1)(50+1)=1+50^2-1=2500