Question 983566
What do you want?  Combine like terms, maybe?   You have four terms, so maybe it is already simplified.  Factorize?  Each of the four terms contains a factor of {{{sqrt(b)}}}.


Maybe you may put as  {{{(3a*sqrt(3)+a*sqrt(5)+a*sqrt(3)-4b*sqrt(5))*sqrt(b)}}}.


What more?  Move the terms of {{{sqrt(3)}}} and {{{sqrt(5)}}} ?
{{{(3a*sqrt(3)+a*sqrt(3)+a*sqrt(5)-4b*sqrt(5))*sqrt(b)}}}
{{{(4a*sqrt(3)+(a-4b)sqrt(5))*sqrt(b)}}}