Question

[Trần Minh Đạt]

Tu tỉ lệ thuc \(\frac{a}{b}\)=\(\frac{c}{d}\)suy ra ti lệ thuc \(\frac{a-b}{a+b}\)=\(\frac{c-d}{c+d}\)

Answer 1

[Love Scenario]

ta có:\(\frac{a}{b}=\frac{c}{d}=k\)

          =>a=bk, c=dk

Ta có:\(\frac{a-b}{a+b}=\frac{bk-b}{bk+b}=\frac{b\left(k-1\right)}{b\left(k+1\right)}=\frac{k-1}{k+1}\)(1)

          \(\frac{c-d}{c+d}=\frac{dk-d}{dk+d}=\frac{d\left(k-1\right)}{d\left(k+1\right)}=\frac{k-1}{k+1}\)(2)

Từ (1) và (2) suy ra \(\frac{a-b}{a+b}=\frac{c-d}{c+d}\)

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