9514 1404 393
Answer:
a) 1120
Explanation:
If 28 and 40 are denominators of fractions, one way to find a common denominator is to simply multiply these values:
28×40 = 1120 . . . . a possible common denominator
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The Least Common Denominator is the least common multiple (LCM) of these denominator numbers. The LCM is their product, divided by their greatest common factor. Here, that factor is 4, so the least common denominator is 1120/4 = 280.