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\(\displaystyle -\frac{7}{12}-\frac{1}{2}=-\frac{7}{12}-\frac{6}{6}\ \frac{1}{2}=-\frac{7}{12}-\frac{6}{12}=\frac{1}{12}(-7-6)=\frac{1}{12}(-13)=-\frac{13}{12}\)
 
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