log₂x + log₅x= lgx / (lg2*lg5)
log₂x + (log₂x)/(log₂5 )= lgx / (lg2*lg5)
log₂x(1+log₅2)= lgx / (lg2*lg5)
log₂x * log₅10 = lgx / (lg2*lg5)
log₂x= lgx / lg2
log₂x = log₂x
х = х
х > 0