Question 145228
{{{sqrt(5a)+ 2sqrt(45a^3)}}} 
= {{{sqrt(5a)+ 2sqrt(5a*9a^2)}}}
= {{{sqrt(5a)+ 2sqrt(5a)*sqrt(9a^2))}}}
= {{{sqrt(5a)+ 2sqrt(5a)*3a)}}}
= {{{sqrt(5a)+ sqrt(5a)*6a)}}}
= {{{(1+ 6a)*sqrt(5a))}}}

The book is right. I have seen the book be wrong, but it's rare.