Find the LCD:
a) (12/55c^6) (4/11c^9)
b) (9/4c+12) (5c/5c+10)
c) (9x/x^2-4x+4) (5x/x^2-5x+6)
d) (7/x) (3/42-7x) (x/x^2-36)
55c^6 = 5*11*c^6
11c^9 = 11*c^9
LCD = 5*11*c^9
Do the others in like wise. LCD will have the highest power of any of the prime factors or variables.