Question 30314
2(x+h)^2 - 2x^2
----------------  
     h

= 2[(x+h)^2 - x^2]/h
= 2[(x^2+2xh+h^2)-x^2]/h  
(using formula (a+b)^2= a^2+2ab+b^2 and here a = x and b=h)
= 2[(x^2-x^2)+2xh+h^2]/h   (grouping like terms which is nothing but the applying of additive commutativity and additive associativity repeatedly)
=2[(0)+2xh+h^2]/h
=2X[2xh+h^2]/h
=2X h[2x+h]/h (taking h out)
=2(2x+h) (cancelling h)
Answer: 2(2x+h)