Find the least common denominator for the following rational expressions.
18 -5r st7
r-4';2-5r+4' m2 - 4r - 5
(r- 1)(r-4)(r-5)
(t-1)(r + 4){r – 5)
(r- 1)(r + 1)(r = 4){r - 5)
(r - 1)(r + 1)(r + 4)(r-5)
DONE