A) you cannot combined square roots if the radicands aren't the same.
Its like variables. You can only add like terms. IE You cannot add 2x +3y.
Its the only rule that applies to the problem.
we know that
In a right triangle
Applying the Pythagorean Theorem

where
a and b are the legs of the triangle
c is the hypotenuse of the triangle
Step N 
<u>Assume that the third side is a leg</u>
In this case we have


Solve for b

substitute the values



Step N 
<u>Assume that the third side is the hypotenuse</u>
In this case we have


substitute the values



Step N 
<u>Find the difference of the third sides</u>

therefore
<u>the answer is</u>

A=l*w
=> A/w=l
you have to perform polynomial division
l=x^2+5x+13+54/(x-4)