Answer:
(m, a, b, c) ∈ {(1, 196, 441, 210), (7, 28, 63, 30)}
Explanation:
m is a common factor of 196, 210, 441
The prime factors of those numbers are
... 196 = 2²×7²
... 210 = 2×3×5×7
... 441 = 3²×7²
7 is the only prime factor common to all the numbers. Hence the possible values of m are 1 and 7.
For m = 1, (a, b, c) = (196, 441, 210).
For m = 7, (a, b, c) = (196, 441, 210)/7 = (28, 63, 30).