Question

Tìm x biết :\(\dfrac{2x-5}{6}=\dfrac{x-7}{5}\)

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

Answer 1

**\(\dfrac{2x-5}{6}=\dfrac{x-7}{5}\Leftrightarrow\dfrac{6\left(2x-5\right)}{30}=\dfrac{5\left(x-7\right)}{30}\)

\(\Leftrightarrow6\left(2x-5\right)=5\left(x-7\right)\Leftrightarrow12x-30=5x-35\)

\(\Leftrightarrow12x-5x=-35+30\Leftrightarrow7x=-5\Leftrightarrow x=-\dfrac{5}{7}\)

**\(\dfrac{4x+1}{3}=\dfrac{2x-3}{4}\Leftrightarrow\dfrac{4\left(x+1\right)}{12}=\dfrac{3\left(2x-3\right)}{12}\)

\(\Leftrightarrow4\left(x+1\right)=3\left(2x-3\right)\Leftrightarrow4x+4=6x-9\)

\(\Leftrightarrow4x-6x=-9-4\Leftrightarrow-2x=-13\Leftrightarrow x=\dfrac{13}{2}\)