Question

tìm x biết 2a-ab+b=0

a² +ab-2=0

Answer 1

\(2a-ab+b=0\)

\(\Rightarrow a\left(2-b\right)+\left(2-b\right)=2-0\)

\(\Rightarrow\left(a-1\right)\left(2-b\right)=2\)

\(\Rightarrow\left(a-1\right);\left(2-b\right)\inƯ\left(2\right)=\left\{\pm1;\pm2\right\}\)

Ta có các trường hợp sau:

\(TH1:\hept{\begin{cases}a-1=1\\2-b=2\end{cases}\Leftrightarrow\hept{\begin{cases}x=2\\b=0\end{cases}}}\)

\(TH2:\hept{\begin{cases}a-1=-1\\2-b=-2\end{cases}\Leftrightarrow\hept{\begin{cases}a=0\\b=4\end{cases}}}\)

\(TH3:\hept{\begin{cases}a-1=2\\2-b=1\end{cases}\Leftrightarrow\hept{\begin{cases}a=3\\b=1\end{cases}}}\)

\(TH4:\hept{\begin{cases}a-1=-2\\2-b=-1\end{cases}\Leftrightarrow\hept{\begin{cases}a=-1\\b=3\end{cases}}}\)

Vậy............................