evvoronina1 1/2^(х-1) + 1/2 • 1/2(х-1) + 1/2 • 1/2 • 1/2^(х-1) <56
1/2^(х-1) • (1/2 + 1/4 + 1/8) < 56
1/2^(х-1) • (4/8 + 2/8 + 1/8) < 56
1/2^(х-1) • 7/8 < 56
1/2^(х-1) < 56•8/7
1/2^(х-1) < 64
1/2^х • 1/2^(-1) < 64
1/2^х • 2 < 64
1/2^х < 32
1/2^х < 2^5
х < 5