Упростите выражения пожалуйста

1) 4,2m(-1.8)(-2.5n) = -7.56m(-2.5n) = 18.9mn
2) 16/9 a (-3/4c) * 7/3 = -2/3ac * 7/3 = -14/9 ac
3) -6x3y(-5c) = -18xy(-5c) = 90xyc
4) -16.2p(- 2/9)(-5/18) = -16.2p * 5/81 = -0.1p
5) n-5.8-4.9-n = -10.7
6)20mn*8k = 160mnk
7) -19.5a *5/8b * 5/6 = -975/96ab = - 10целых 15/96  ab = -10 целых 5/32 ab
8) 7.2-a+4.7+a-7.2-9.3 = 4.7-9.3 = -4.6
9) 3.8x(-0.35y)(-4.3) = -1.33xy(-4.3) = 5.719xy
10) c+5.5-4.9-c = 0.6
11) 9/16p(-4/3) * 3/7 = -3/2p * 3/7 = -9/14p
12) 21k(-4p) = -84kp
13) 8/15x (-5/2) (-3/2) = -4/3x (-3/2) = 2x
14) 4.8+a-13.9-b+a-4.8 = 2a-b-13.9
15) 7.68mnp
16) 8c (-3/7) = -24/7c
17) -n+4.8-3.8+n = 1