Запись логарифмов: log(основание, число).
{log(1/2, x²) ≥ log(1/2, 28) - log(1/2, 7),
{log(3, (4x-1)) > 0;
{log(1/2, x²) ≥ log(1/2, (28/7)),
{log(3, (4x-1)) > log(3, 1);
{log(1/2, x²) ≥ log(1/2, 4),
{4x-1 > 1;
{x² ≤ 4,
{4x > 2;
{x² - 4 ≤ 0,
{x > 1/2;
{(x-2)(x+2) ≤ 0,
{x > 1/2;
{-2 ≤ x ≤ 2,
{x > 1/2;
х ∈ (1/2; 2].
Ответ: (1/2; 2].