1) 10х + 20 + 10 = 50
10х = 50 - 20 - 10
10х = 20
х = 2
2) х + 12 - 10 - 3 = 7
х = 7 - 12 + 10 + 3
х = 8
3) х - 10 - 7 + 3 = -5
х = -5 + 10 + 7 - 3
х = 9
1) 10х + 20 + 10 = 50
10х = 50 - 20 - 10
10х = 20
х = 2
2) х + 12 - 10 - 3 = 7
х = 7 - 12 + 10 + 3
х = 8
3) х - 10 - 7 + 3 = -5
х = -5 + 10 + 7 - 3
х = 9