一:若a/b=c/d=e/f=2/5,求(1)(a-c)/(b-d) ; (2)(2a+3c-4e)/(2b+3d-4f) (3)比较的结论,发现什么规律
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![一:若a/b=c/d=e/f=2/5,求(1)(a-c)/(b-d) ; (2)(2a+3c-4e)/(2b+3d-4f) (3)比较的结论,发现什么规律](/uploads/image/z/3711525-69-5.jpg?t=%E4%B8%80%EF%BC%9A%E8%8B%A5a%2Fb%3Dc%2Fd%3De%2Ff%3D2%2F5%2C%E6%B1%82%EF%BC%881%EF%BC%89%EF%BC%88a-c%29%2F%28b-d%29+%3B+%282%29%282a%2B3c-4e%29%2F%282b%2B3d-4f%29+%283%29%E6%AF%94%E8%BE%83%E7%9A%84%E7%BB%93%E8%AE%BA%2C%E5%8F%91%E7%8E%B0%E4%BB%80%E4%B9%88%E8%A7%84%E5%BE%8B)
一:若a/b=c/d=e/f=2/5,求(1)(a-c)/(b-d) ; (2)(2a+3c-4e)/(2b+3d-4f) (3)比较的结论,发现什么规律
一:若a/b=c/d=e/f=2/5,求(1)(a-c)/(b-d) ; (2)(2a+3c-4e)/(2b+3d-4f) (3)比较的结论,发现什么规律
一:若a/b=c/d=e/f=2/5,求(1)(a-c)/(b-d) ; (2)(2a+3c-4e)/(2b+3d-4f) (3)比较的结论,发现什么规律
令m=2/5 (因为2/5写起来太麻烦了,没有别的意思)
a/b=m
所以a=bm
同理可得,c=dm,e=fm
(1)(a-c)/(b-d)
=(bm-dm)/(b-d)
=m(b-d)/(b-d)
=m
=2/5
(2)(2a+3c-4e)/(2b+3d-4f)
=(2bm+3dm-4fm)/(2b+3d-4f)
=m(2b+3d-4f)/(2b+3d-4f)
=m
=2/5
(3)规律嘛,只要分子分母乘以相同的系数,分数的值不变