It it is the first choice i mentioned then B is the answer.
Prime factors of 42: 2x7x3
prime factors of 126: 2x3x3x7
prime factors of 210: 7x3x5x2
now we multiply all the factors that they all have in common: 2x3x7 which is 42. So the highest common factor is 42
Answer:
A: 8(8+7)
B: 2(32+28)
Step-by-step explanation:
8(8+7) = 64+56
2(32+28) = 64+56