r^2-25/r+3*1/r^2+5r-r+5/r^2-3r

Question

r^2-25/r+3*1/r^2+5r-r+5/r^2-3r

Comments

помогите 80 балов дам

Answer 1

1) r^2-25/r+3*1/r^2+5r=(r-5)(r+5)/r+3*1/r(r+5)=r-5/r(r+3)
2) r-5/r(r+3)-r+5/r^2-3r=(r-5)(r-3)-(r+5)(r+3)/r(r+3)(r-3)=r^2-8r+15-r^2-8r-15/r(r+3)(r-3)=16r/r(r+3)(r-3)=16/9-r^2