Cho \(\dfrac{a}{b}=\dfrac{c}{d}.\) Chứng minh \(\dfrac{a^2-2b^2}{(a+4b)^2}=\dfrac{c^2-2d^2}{(c+4d)^2}\).

Cho \(\dfrac{a}{b}=\dfrac{c}{d}\). Chứng minh \(\dfrac{a-2c}{3a+b}=\dfrac{b-2d}{3b+d}\).

Cho \(\dfrac{a}{b}=\dfrac{c}{d}\). Chứng minh \(\dfrac{a-2b}{b}=\dfrac{c-2d}{d}.\)

Cho \(\dfrac{a}{b}=\dfrac{c}{d}\). Chứng minh:

a) \(\dfrac{a-2b}{b}=\dfrac{c-2d}{d};\)                                 b) \(\dfrac{a-2c}{3a+b}=\dfrac{b-2d}{3b+d}\);

c) \(\dfrac{a^2-2b^2}{(a+4b)^2}=\dfrac{c^2-2d^2}{(c+4b)^2}\).

\(\dfrac{a^2+c^2}{b^2+d^2}\) có = \(\dfrac{(a+c)^2}{(b+d)^2}\) ko mn nhỉ?

Cho \(\dfrac{a}{b}=\dfrac{c}{d}.\) Chứng minh \(\dfrac{(a+c)^2}{(b+d)^2}=\dfrac{a.c}{b.d}\).