9514 1404 393
Answer:
b. 60
Explanation:
The list of factors is 2, 3, 5, 7. The list of common factors is 2, 3, 5. The lowest exponents on those factor are ...
2^2 × 3^1 × 5^1 = 60
The GCF of 720 and 2100 is 60.
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Additional comment
You can verify this using Euclid's method of finding the GCF.
2100/720 = 2 r 660
720/660 = 1 r 60
660/60 = 11 r 0 . . . . 60 is the GCF
Find the remainder from the division. If it is zero, the divisor is the GCF. If it is non-zero, replace the largest number with the remainder, and repeat.