\(x\times\dfrac{1}{2}+x\times\dfrac{1}{3}=\dfrac{5}{6}\\ x\times\left(\dfrac{1}{2}+\dfrac{1}{3}\right)=\dfrac{5}{6}\\ x\times\dfrac{5}{6}=\dfrac{5}{6}\\ x=\dfrac{5}{6}:\dfrac{5}{6}\\ x=1\)
b,\(4\dfrac{1}{2}\times x-2\dfrac{1}{2}\times x=1\dfrac{1}{2}\\ \dfrac{9}{2}\times x-\dfrac{5}{2}\times x=\dfrac{3}{2}\\ \left(\dfrac{9}{2}-\dfrac{5}{2}\right)\times x=\dfrac{3}{2}\\ 2\times x=\dfrac{3}{2}\\ x=\dfrac{3}{2}:2\\ x=\dfrac{3}{4}\)