Question

a,tìm số nguyên x,y biết :

x-1/-4=-4/x-1

x-4/6=-1/3

Answer 1

a) Ta có: \(\dfrac{x-1}{-4}=\dfrac{-4}{x-1}\)

\(\Leftrightarrow\left(x-1\right)^2=16\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=4\\x-1=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-3\end{matrix}\right.\)

Vậy: \(x\in\left\{5;-3\right\}\)

b) Ta có: \(\dfrac{x-4}{6}=\dfrac{-1}{3}\)

\(\Leftrightarrow x-4=-2\)

hay x=2

Vậy: x=2

Answer 2

a/ 

\(x-\dfrac{1}{-4}=-\dfrac{4}{x-1}\)

\(x+\dfrac{1}{4}+\dfrac{4}{x-1}=0\)

\(\dfrac{x\left(x-1\right)4}{4\left(x-1\right)}+\dfrac{16}{4\left(x-1\right)}=0\)

\(4x\left(x-1\right)+16=0\)(quy tắc khử mẫu lớp 8)

\(4x^2-4x+16=0\)

\(4x^2-2x-2x+16=0\)

\(\left(4x^2-2x\right)-\left(2x-16\right)=0\)

\(2x\left(2x-1\right)-2\left(x-16\right)=0\)