Решить систему

3,9, 1/5 - основание логарифма

log (3) x+log (9) y=3

log (9) y=3-log (3) x

log (3) y/2=3-log (3) x

log (3) y=6-2log (3) x

Подставим во 2

log (1/5) x+log (3) y=3

log (1/5) x+6-2log (3) x=3

-log (3) x/log (3) 5 - 2log (3) x+3=0

-log (3) x-2log (5) 3*log (3) x+3log (3) 5=0

-log (3) x * (1+2log (3) 5) = - 3log (3) 5

log (3) x=3log (3) 5 / (1+2log (3) 5)

log (3) x = log (3) 125/log (3) 75=log (75) 125

x=3^log (75) 125