Question 1094767
<pre>
(3x y)(7x 2y),  6 & 7 does not work


(3x 2y)(7x y),  3 & 14 may work
 
(3x-2y)(7x+y),  3-14=-11

(3x+2y)(7x-y),  -3+14=11
</pre>

{{{21x^2+11xy-2y^2=highlight((3x+2y)(7x-y))}}}