What is r-1-2r less than or equal to -2? i need to show my work also.

(r -1 -2r) <= -2.  Simplify.

r -2r  <= -2 +1.

-r    <=  -1.    Divide both sides by -1 and reverse the sign. Recall in inequality
                    when you multiply or divide by negative, the inequality sign is
                    reversed.
r  >=  -1/-1

r >= 1.

That's it.