А) (-8.5) · 20/17 + (91/46 - 53/23) ÷ 30/23 =
= -(85·20)/(10·17) + (91/46 - 106/46) · 23/30 = -10 - 15·23/30 =
= -10 - 23/2 = -10 - 11.5 = -21.5
б) (-7/6)² · (-5/7)² · (-2.88) = 49/36 · 25/49 · (-2.88) =
= 25/36 · (-288/100) = - (25·288)/(36·100) = -8/4 = -2