Решите уравнения. 7х + 2х =27 7х - 5x =70 x + 123 = 562 16х - 4х = 60 4x + 12x = 20 + 12 621 - x = 235

7х+2х=27
9х=27
х=27:9
x=3;

7x-5x=70
2x=70
x=35

x+123=562
x=562-123
x=439

16х - 4х = 60
12x=60
х=5

 4x + 12x = 20
16х=20
х=20/16
х=5/4   или х=1,25

12 621 - x = 235
х=12621-235
х=12386