\(\frac{x - 3}{13}+\frac{x - 3}{14}=\frac{x - 3}{15}+\frac{x - 3}{16}\) ​

\(\frac{x - 3}{13} + \frac{x - 3}{14} - \frac{x - 3}{15} - \frac{x - 3}{16} = 0\)

\(\left(\right.x-3\left.\right)\left(\right.\frac{1}{13}+\frac{1}{14}-\frac{1}{15}-\frac{1}{16}\left.\right)=0\)

\(x + 3 = 0\) vì \(\left(\right.\frac{1}{13}+\frac{1}{14}-\frac{1}{15}-\frac{1}{16}\left.\right)\) ≠ 0

\(x = - 3\)

Vậy x = -3

\(\frac{x-3}{13}+\frac{x-3}{14}=\frac{x-3}{15}+\frac{x-3}{16}\)

\(\frac{x-3}{13}+\frac{x-3}{14}-\frac{x-3}{15}-\frac{x-3}{16}=0\)

\(\left(x-3\right)\left(\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{16}\right)=0\)

\(x+3=0\) vì \(\left(\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{16}\right)\) ≠ 0

\(x=-3\)

Vậy x = -3