Вычислите удобным способом:

а) 3/5 : (7/60) : (-3 11/15) * 1 2/3

б) 2 2/7*3 8/15 + 1 7/15 * 2 2/7 - 72/7 * 5

3/5: (7/60) : (-3 11/15) * 1 2/3=

= 3/5 * 60/7 : ( - 56/15) * 5/3 = 36/7 * (-15/56) * 5/3 =

= - (36*15*5) / (7*56*3) = - 9*25/7*14=-225/98 = - 2 29/98

2) 2 2/7 * 3 8/15 + 1 7/15 * 2 2/7 - 72/7*5 =

= 2 2/7 (3 8/15 + 1 7/15) - 72/7*5=

=14/7 * 5 - 72/7 * 5 = 5/7 (14-72) = 5/7 * (-58) = - 290/7 = - 41 3/7