(Toán 8) Bài toán đại khó

V

vansang02121998

Ta có

$b^2=ac \Rightarrow \frac{a}{b}=\frac{b}{c}$

$c^2=bd \Rightarrow \frac{b}{c}=\frac{c}{d}$

$\Rightarrow \frac{a}{b}=\frac{b}{c}=\frac{c}{d}$

$\Rightarrow \frac{a}{b}.\frac{b}{c}.\frac{c}{d}=\frac{a^3}{b^3}=\frac{b^3}{c^3}=\frac{c^3}{d^3}=\frac{a^3+b^3+c^3}{b^3+c^3+d^3}$

$\Leftrightarrow \frac{a}{d}=\frac{a^3+b^3+c^3}{b^3+c^3+d^3}$
 
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