Originally Posted by

**mike_302** Let's say we have 3n^2+12n=k ---> 3(n^2+4n)=k

I've noticed that I cannot take that three from the left side and move it to the right (my dividing) before completing the square and using that three to multiply the negative number I get 3(n^2+4n+4-4)=k ----> 3*-4 .....

But I'm not understanding why I cannot move that 3 over before hand. Can someone explain this in the simple terms I would understand. I'm decent with my math, but .... Well, use your own explanatory discretion.