Question 45481
{{{(-2r^4+9r^3-3r)-(8r^4-9r^3+6r^2-2r)}}}
{{{-2r^4 + 9r^3 - 3r - 8r^4 + 9r^3 - 6r^2 + 2r}}}
{{{-2r^4 - 8r^4 + 9r^3 + 9r^3 - 6r^2 + 2r - 3r}}}
{{{-10r^4 + 18r^3 - 6r^2 - r}}}