cho a/b=b/c=c/a CM:(a+b+c/b+c+d) mũ 3=a/d

1 câu trả lời

Đáp án:

Giải thích các bước giải:

$\dfrac{a}{b}=\dfrac{b}{c}=\dfrac{c}{d}=\dfrac{a+b+c}{b+c+d}\\

\rightarrow \dfrac{a^{3}}{b^{3}}=\dfrac{b^{3}}{c^{3}}=\dfrac{c^{3}}{d^{3}}=\dfrac{(a+b+c)^{3}}{(b+c+d)^{3}}=\dfrac{a}{b}.\dfrac{b}{c}.\dfrac{c}{d}=\dfrac{a}{d}\\

\rightarrow \dfrac{(a+b+c)^{3}}{(b+c+d)^{3}}=\dfrac{a}{d}\\$