1.
2x = 18-4x
2x+4x = 18
6x = 18
x = 18:6
x = 3
xx-Проверка:
2x = 2*3 = 6
18-4x = 18-4*3 = 18-12 = 6
6 = 6
2.
9x+45 = 36+7x
9x-7x = 36-45
2x = -9
x = -9:2
x = -4,5
Проверка:
9x+45 = 9*(-4,5)+45 = -40,5+45 = 4,5
36+7x = 36+7*(-4,5) = 36-31,5 = 4,5
4,5 = 4,5
3.
89x-23 = 48-5x
89x+5x = 48+23
94x = 71
x = 71/94
Проверка:
89x-23 = 89*71/94-23 = 6319/94-2162/94 = 4157/91 = 45 62/91
48-5x = 48-5*71/94 = 4512/94-355/94 = 4157/91 = 45 62/91
45 62/91 = 45 62/91