Express in terms of x and y:?

If log 4 =x and log 5 =y, express each of the following in terms of x and y:





a) log 25





b) log (5/4)





c) log (sqrt 20)

Express in terms of x and y:?
log4=x, log5=y





a)log25=log(5x5)=log5+log5,=y+y, =2y





b)log(5/4)=log5-log4, =y-x





c)log(rt20)=log(rt5)(rt4), =log rt5 +log rt4, =rty+rtx


I'm not positive about c)