Question 312717
20cd/c^2-d^2 - c-d/c+d


20cd / (c+d)(c-d) - c-d / c+d
LCM = (c+d)(c-d)

20cd-(c-d)^2 / (c+d)(c-d)
20cd -c^2+2cd-d^2 / (c+d)(c-d)
-c^2-18cd-d^2 / (c+d)(c-d)