Question

tìm x trong các tỉ lệ thức sau :

7/x-1=x+1/9

x-1/x+2=x-2/x+3

làm giúp mk nhoaaaaaaaaaaaaaaaaa

Answer 1

\(\frac{7}{x-1}=\frac{x+1}{9}\)

\(\Rightarrow\left(x-1\right)\left(x+1\right)=7.9\)

\(\Rightarrow x^2-1=63\)

\(\Rightarrow x^2=64\)

\(\Rightarrow\orbr{\begin{cases}x=8\\x=-8\end{cases}}\)

\(\frac{x-1}{x+2}=\frac{x-2}{x+3}\)

\(\Rightarrow\left(x-1\right)\left(x+3\right)=\left(x+2\right)\left(x-2\right)\)

\(\Rightarrow x^2+2x-3=x^2-4\)

\(\Rightarrow2x-3=4\)

\(\Rightarrow2x=7\)

\(\Rightarrow x=\frac{7}{2}\)