5xy + 4x -7xy=
2/3 x^2 . 1/4 xy=
9 x^2 + 5 x^2 + 3 - x=
5a . (- 1/5 a)=
4 x^3 y . 2 x=
-8xy - 8x - 2xy=
-5x . (-5 xy)=
25 x^2 y
2/12 x^3 y
- a^2
14 x^2 - x + 3
8 x^4 y
-2xy + 4x
-10 xy - 8x
