Question 1040657
(x^2y-xy+x^2) + (2x^2+3xy-x^2 y) + (3x^2 -y^2  +x^2 y) 
Add or subtract like terms.
There are 3 x^2y terms, two positive and one negative, so there is 1 positive x^2 y
There is a minus xy and +3 xy, so there are 2 positive xy terms
There is an x^2, a 2x^2 and a 3x^2 for 6 x^2
I count the terms that I have used.  So far, I have used 8, but there is a ninth.
It is -y^2
I collect the terms
6x^2+2xy+x^2y-y^2