[tex]a)~~2\cdot (\frac{1}{2} )^{3} +3\cdot \frac{1}{2} \cdot \frac{2}{3} +(\frac{2}{3} )^{2} =2\cdot \frac{1}{8} +1+\frac{4}{9} =\frac{1}{4} +1+\frac{4}{9} =\frac{9}{36} +1+\frac{16}{36}=1\frac{25}{36} \\\\b)~~2\cdot (-1)^{4} -[(-1)\cdot (-\frac{1}{2} )]+2\cdot (-\frac{1}{2} )^{2} =2\cdot 1 -\frac{1}{2} +2\cdot \frac{1}{4} =2-\frac{1}{2} +\frac{1}{2} =2[/tex]
