log5 x =2 * log5 3 + 4 * log25 2;

Найдем х.

log5 x = 2 * log5 3 + 4 * 1/2 * log5 2;

log5 x = 2 * log5 3 + 2 * log5 2;

log5 x = log5 9 + log5 4;

log5 x = log5 36;

x = 36.