(3a+2b)(2b-3a)=4b²-9a²
(-4n³+n)(4n³+n)=n²-16n^6
-------------------------------
2b(a²+b³)=2a²b+2b^4
2b³(a²+b³-c)=2a²b³+2b^6-2b³c
------------------------------
(x+1)(x+2)=x²+2x+x+2=x²+3x+2
(2m+n²)(2n-m²)=4mn-2m³+2n³-n²m²
---------------------------------
(x²+2y)(x²+2y)-(x²-2y)(x²+2y)=x^4+2x²y+4y²-x^4+4y²=2x²y+8y²
----------------------------
2a+3b-5a-3b=-3a
5x-3y+2x+3y=7x