Question 124991
I'LL GIVE YOU AN EXAMPLE THAT MIGHT EXPLAIN HOW I GOT THE MIDDLE TERMS.
MULTIPLY 63 BY 22.
-------63
-------22
---------------------------------
------126
-----126
--------------------------------
-----1386 WHERE DID I GET THE 3 & 8?
ANSWER - BY ADDING THE INTERIM (MIDDLE) VALUES. 

ONE WAY TO SEE HOW THIS IS ACCOMPLISHED IS TO MULTIPLY USING THE OLD FASHIONED METHOD AS FOLLOWS:
3X-2Y
3X-2Y
------------------------------
9X^2-6XY-6XY+4Y^2 THE 9X^2=3X*3X, THE -6XY=3X*-2Y, THE OTHER -6XY=-2Y*3X & 
-2Y*-2Y=4Y^4 NOW COMBINE THE XY TERMS.
9X^2-12XY+4Y^2