$12x^3+6x^2y+20xy+10y^2$

$12x^3+20x^2y+6xy+10y^2$

$10x^3+6x^2y+20xy+10y^2$

$10x^3+6x^2y+20xy+12y^2$

$21a^8b^5$

$-21a^8b^4c$

$21a^8b^4c$

$18m^4-12m^3n+15m^2n^4$

$-18m^3+15m^2n+12m^2n^4$

$18m^4-12mn+15n^4$

7tu

8tu

7u

8u

 $44x^7y^4$  

 $-42x^7y^4$  

 $-47x^7y^4$  

 $42x^7y^4$  

 $11m^2$  

 $12n^2$  

 $11m^2n$  

 $12m^2n$  

$4xy-9xy$

$6x^2y^5-9xy^2$

$6x^3y^4-9xy^2$