номер 644 пожайлуста

2.
2,81*12,1 - (-4,8)*2,81 = 2,81(12,1 - (-4,8)) = 2,81*(12,1+4,8) = 2,81*16,9 = 47,489
3.
(1,4+х)*5 = 10 1/8
1,4+х = 10 1/8 :5
1,4+х = 81/8*1/5
1,4+х = 81/40
х = 81/40-1,4
х=81/40-14/10
х =81/40-56/40
х= 25/40
х = 5/8
1.
а) = 1 21/26
б) = 27/84 = 9/28
г) = 4/3 = 1 1/3