cho `a/b=c/d` cm `{a-2b}/b={c-2d}/d`

2 câu trả lời

Theo đề bài, ta có:

`a/b=c/d`

`→a/b-2=c/d-2`

`→a/b-2/b=c/d-2/d`

`→{a-2}/b={c-2}/d`

 

Đặt $\dfrac{a}{b}=\dfrac{c}{d}=k(k\ne 0)$

$=>a=bk,c=dk\\\dfrac{a-2b}{b}=\dfrac{bk-2b}{b}=k-2\\\dfrac{c-2d}{d}=\dfrac{dk-2d}{d}=k-2\\=> \dfrac{a-2b}{b}=\dfrac{c-2d}{d}$