Question

Tìm x biết

\(\frac{x+1}{x-2}=\frac{3}{4}\)

\(\frac{2x-3}{x+1}=\frac{4}{7}\)

Answer 1

\(\frac{x+1}{x-2}=\frac{3}{4}\) ( \(ĐKXĐ\) : \(x\ne2\) )

\(\Leftrightarrow\left(x+1\right).4=\left(x-2\right).3\)

\(\Leftrightarrow4x+4=3x-6\)

\(\Leftrightarrow4x-3x=-6-4\)

\(\Leftrightarrow x=-10\)

b ) \(\frac{2x-3}{x+1}=\frac{4}{7}\left(ĐKXĐ:x\ne1\right)\)

\(\Leftrightarrow7\left(2x-3\right)=4\left(x+1\right)\)

\(\Leftrightarrow14x-21=4x+4\)

\(\Leftrightarrow10x=25\)

\(\Leftrightarrow x=\frac{5}{2}\)