Could you guys do these questions step by step? I have some difficulty understanding =/

$\displaystyle 1) (3x^3+5x^4+4x^2+1)+(2x^3+3x-12x^4-1)$

$\displaystyle 2) (y^3+7y+6y^2-6)-(7+6y+5y^3+4y^4)$

$\displaystyle 3) (4-6x-x^3-x^4)-(2+3x^3+7x+5x^2)$

$\displaystyle 4) (x+y)(x+2y)(2x-y)$

$\displaystyle 5) (y^2+4)\div(y+1)$

$\displaystyle 6) (2a^3-11a^2+7a-10)\div(a-5)$

$\displaystyle 7) 4(b^3+5b+2+4b^2)\div(1+2b)$

$\displaystyle 8) (x^3-2x^2-75)\div(x-5)$

$\displaystyle 9) (6n^3+5n^2+10-13n)\div(3n-5)\$

$\displaystyle 10) (2x^3-3x^2y-3xy^2-5y^3)\div(x^2+xy+y^2)$

Thank you very much!!