[tex]1).- \frac{5}{6} - \frac{1}{7} *(- \frac{7}{4} )=- \frac{5}{6} + \frac{7}{28} =- \frac{70}{84} + \frac{21}{84} =- \frac{49}{84} =- \frac{7}{12} [/tex]
[tex]2). \frac{x-1}{2} - \frac{2x-3}{3} = \frac{x-3}{4} \\ 6(x-1)-4(2x-3)=3(x-3) \\ 6x-6-8x+12=3x-9 \\ 6x-8x-3x=-9+6-12 \\ -5x=-15 \\ x= \frac{-15}{-5} \\ x=3[/tex]