万妖之祖听:1-2×51+51×51,利用乘法公式
来源:百度文库 编辑:高考问答 时间:2024/05/13 05:55:42
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
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来源:百度文库 编辑:高考问答 时间:2024/05/13 05:55:42
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