Answer:
14
Explanation:
You want the greatest common factor of the terms {98ab^3, 84a, 140b, 112ab}.
Common factors
There are no variables that are common to all terms. 'a' and 'b' are each common to 3 of the 4 terms, but not all.
The greatest common factor of the constants cannot be larger than the smallest difference of the constants. That difference is ...
98 -84 = 112 -98 = 14
Since 14 is a divisor of all of the constants, 14 is the greatest common factor.
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Additional comment
Factoring out the greatest common factor, we have ...
= 14{7ab³, 6a, 10b, 8ab}