Решите уравнения:х+12-5х=883а+21а=1002*х*15=12018х-х+9х=104

х + 12 - 5х = 88                               3а + 21а = 100- 4х = 88 - 12                                   24а = 100- 4х = 76                                          а = 100 : 24х = 76 : (- 4)                                     а = 4 4/24 х = - 19                                            а = 4 1/6 2 * х * 15 = 120                               18х - х + 9х = 10430х = 120                                        26х = 104х = 120 : 30                                     х = 104 : 26   х = 4                                                х = 4