[tex]b = - \frac {1}{9} \\ \frac{3}{4}(1 - b) = \frac{3}{4} (1 - ( - \frac{1}{9}) ) = \\ \frac{3}{4} (1 + \frac{1}{9} ) = \frac{3}{4} ( \frac{9}{9} + \frac{1}{9} ) = \\ \frac{3}{4} \times \frac{10}{9} = \frac{1}{2} \times \frac{5}{3} = \frac{5}{6} [/tex]
