Question 519608
Your first step would be to group the like-terms:
{{{(4r^4-4r^3+3r^2+11r-8)+(r^5+10r^3+4r^2-3r+5)+(-7r^4+r^2-5r-8)= (r^5)+(4r^4-7r^4)+(-4r^3+10r^3)+(3r^2+4r^2+r^2)+(11r+(-3r)+(-5r))+((-8)+5+(-8))}}}
Once you have grouped the like-terms, you evaluate each group.
{{{r^5-3r^4+6r^3+8r^2+3r-11}}}