6)
[tex]\frac{3}{4} *(-12)-\frac{1}{5} =(-9)-\frac{1}{5}=-9\frac{1}{5}\\\frac{2}{3}+\frac{1}{2}*\frac{5}{28} +\frac{1}{7}=\frac{2}{3}+\frac{5}{56}+\frac{1}{7}=\\\frac{112}{168}+\frac{15}{168}+\frac{24}{168}=\frac{151}{168}[/tex]
