А)4х-12=18-х;б) 21х-5(2х-7)=24;в)0,15(х-4)=9,9-0,3(х-1)

а) 4х - 12 = 18 - х             б) 21х - 5(2х - 7) = 244х + х = 18 + 12                21х - 10х + 35 = 245х = 30                              11х = 24 - 35х = 30 : 5                           11х = - 11х = 6                                   х = - 11 : 11                                           х = - 1 в) 0,15(х - 4) = 9,9 - 0,3(х - 1)0,15х - 0,6 = 9,9 - 0,3х + 0,30,15х + 0,3х = 9,9 + 0,3 + 0,60,45х = 10,8х = 10,8 : 0,45х = 24