Question

log7 x = log 7 2,5 + log 7 10

Answer 1

Log (7)Х= log (7) 2,5 + log( 7) 10, Х>0

Log (7)Х= log (7) 25

Х=25

Answer 2

$log_{7}(x) = log_{7}(2.5) + log_{7}(10) \\ log_{7}(x) = log_{7}(2.5 \times 10) \\ log_{7}(x) = log_{7}(25) \\ x = 25$

была использована формула:
loga(x)+loga(y)= loga(x×y)