Question 318394
{{{(-5r^2+2r+3)-(7r^2+3)=-5r^2+2r+3-7r^2-3=(-5r^2-7r^2)+2r+(3-3)=-12r^2+2r}}}


So {{{(-5r^2+2r+3)-(7r^2+3)=-12r^2+2r}}}