12 : (4/5х) = 20 : 1/4 5/6 = 15/(2х - 3)
4/5х * 20 = 12 * 1/4 5 : 6 = 15 : (2х - 3)
80/5х = 12 : 4 6 * 15 = 5 * (2х - 3)
16х = 3 90 = 10х - 15
х = 3 : 16 90 + 15 = 10х
х = 3/16 105 = 10х
х = 105 : 10
х = 10,5
(15/2)/(9/2) = х - 3/25
15/2 * 2/9 = х - 3/25
15/9 = х - 3/25
5/3 + 3/25 = х
х = 125/75 + 9/75 = 134/75 = 1 59/75
70 * 1014 = 70980
70 * 8208 = 574560
б) 3086 + а = 3086 + 5783 = 8869
3086 + 2807 = 5893
3086 + 9909 = 12995
в) а - 5017 = 8099 - 5017 = 3082
5919 - 5017 = 902
5098 - 5017 = 81
г) х : 4 = 38728 : 4 = 9682
5016 : 4 = 1254
349824 : 4 = 87456