log5(35)-2log5(7/3)+log5(7)-log5(1.8)

log5(35)-2log5(7/3)+log5(7)-log5(1.8)

答え:
下取り式アプリなど
log5(35)-2log5(7/3)+log5(7)-log5(1.8)
=log5(5)+log5(7)-2log5(7)+2log5(3)+log5(7)-log5(9/5)
=1+log5(9)-log5(9)+log5(5)
=1+1
=2