[tex]\sqrt{40} = 6.32\\\\\\or\\5\sqrt{15} \\\\[/tex]
this is because when 40 is broken down into two numbers (one divisible to get out of the square root, and one not) you get 25 + 15 under the square root. we know that the square root of 25 is 5, so we can put 5 outside the root and leave 15 inside.
-------------- try the next problem, and if you don't understand, please reply back.
answer is for a) [tex]5\sqrt{15}[/tex]
