First two common multiples of 3, 4 and 6
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12 24

Step-by-step explanation:

these are the first in a set of common multiples involving these three numbers

people went from manufacturing one object at a time by hand to manufacturing many objects in factories

c.

step-by-step explanation:

because first you have to add the 4x, 9x, and the 7x together and you get 20x and then you add the last numbers up and you get 5and then you put the subtraction sign in there and that's how you get the answer.