逆用平方差公式
如何应用?例题.
人气:130 ℃ 时间:2020-04-12 22:47:45
解答
用在速算上的吧?
(A+B) *(A-B)= A^2-B^2
63* 57
= (60+3)*(60-3)
= 60^2-3^2
=3600-9
=3591
A^2-B^2 = (A+B) *(A-B)
82^2-18^2
=(82+18)*(82-18)
=100*64
=6400
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