Answer: A=-1/12
Step-by-step explanation:
[tex]\displaystyle\\\frac{1}{2}+(-\frac{5}{6} )+\frac{1}{4}=\\\\\frac{1*6-5*2+1*3}{12} =\\\\ \frac{6-10+3}{12}= \\\\\frac{-1}{12}= \\\\-\frac{1}{12}[/tex]
