СПАСИТЕЕЕимоомг иолп

1)
$\frac{9b}{a - b} \times \frac{a {}^{2} - ab}{45b} = \\ = \frac{1}{a - b} \times \frac{a(a - b)}{5} = \\ = \frac{a}{5}$
при а= -83
$- \frac{83}{5} = - 16 \frac{3}{5} = - 16.6$
2)
$\frac{7b}{a - b} \times \frac{a(a - b)}{14b} = \frac{1}{1} \times \frac{a}{2} = \frac{a}{2}$
при а=-13
$- \frac{13}{2} = - 6.5$
3)
$\frac{4b}{a - b} \times \frac{a(a - b)}{8b} = \frac{1}{1} \times \frac{a}{2} = \frac{a}{2}$
при а = 19
$\frac{19}{2} = 9.5$