78 - х = 30
х = 78 - 30
х = 48
78 - 48 = 30
30 = 30
х : 400 = 22
х = 22 • 400
х = 8800
8800 : 400 = 22
22 = 22
8 • (16 + 4) = 8 • 20 = 160
