[tex]-5\dfrac{1}{6}-\left(-8\dfrac{1}{2}\right)=-5\dfrac{1}{6}+8\dfrac{1}{2}\\\\\text{Use commutative property a + b = b + a}\\\\=8\dfrac{1}{2}+\left(-5\dfrac{1}{6}\right)=8\dfrac{1}{2}-5\dfrac{1}{6}\\\\\text{We must fin the common denominator}\\\\\text{6 is the multiple of 2}, \text{therefore the common denomintor is 6.}\\\\=8\dfrac{1\cdot3}{2\cdot3}-5\dfrac{1}{6}=8\dfrac{3}{6}-5\dfrac{1}{6}=(8-5)+\left(\dfrac{3}{6}-\dfrac{1}{6}\right)=3\dfrac{2}{6}=3\dfrac{2:2}{6:2}=\boxed{3\dfrac{1}{3}}[/tex]
