The LCD is 12x(x+1).  Put that over 1, like this 

Multiply every term on both sides by it, like this:



Then cancel like this:



and what's left is



We don't need to write the 1's in the denominators, so we have:



Distribute:



Combine like terms on the left:



Swap sides to get the x² term on the left



Subtract the entire right side from both sides to get 0 on the right



That factors as






Edwin