Question

[Nguyễn Tùng Lâm]

Tìm x,y \(\in\)Z, biết:

a)\(\frac{x}{7}=\frac{5}{y}\)và x>y

b)\(\frac{2}{x}=\frac{x}{-7}\)và x>0

Answer 1

[tth_new]

a) \(\frac{x}{7}=\frac{5}{y}\left(ĐK:x>y\right)\)

\(\Leftrightarrow5.7=x.y\)

\(\Rightarrow\orbr{\begin{cases}x=7\\y=5\end{cases}}\)(Vì x > y)

b) \(\frac{2}{x}=\frac{x}{-7}\left(ĐK:x>0\right)\)

\(\Leftrightarrow2.\left(-7\right)=x.x\)

\(\Leftrightarrow\left(-14\right)=x^2\)

\(\Rightarrow x=\sqrt{14}\)