Answer:
See below for answers
Step-by-step explanation:
Problem A:
[tex]2x^2+8x-1+5x^2-2x-8[/tex]
[tex]2x^2+5x^2+8x-2x-1-8[/tex]
[tex]7x^2+6x-9[/tex]
Problem B:
[tex]-5x^2-2x+10-x^2+7x+5[/tex]
[tex]-5x^2-x^2-2x+7x+10+5[/tex]
[tex]-6x^2+5x+15[/tex]
Problem C:
[tex]4x^2y-2xy^2+9xy^2-x^2y[/tex]
[tex]4x^2y-x^2y-2xy^2+9xy^2[/tex]
[tex]3x^2y+7xy^2[/tex]
Problem D:
[tex]7x^2-2x^2y+4xy^2-y^3+2x^2+9x^2y+4y^3[/tex]
[tex]7x^2+2x^2-2x^2y+9x^2y-y^3+4y^3+4xy^2[/tex]
[tex]9x^2+7x^2y+3y^3+4xy^2[/tex]
