Final answer:
The equation to find the number of marbles per bag when Harold has 7 bags with a total of 42 marbles is 7x = 42. By dividing both sides by 7, it's determined that x, the number of marbles in each bag, is 6.
Step-by-step explanation:
To find the equation that could be used to determine the number of marbles x in each bag when Harold has a total of 42 marbles in 7 bags, you would set up the following equation:
7x = 42.
This equation indicates that 7 times the number of marbles per bag equals the total number of 42 marbles. To solve for x, you would divide both sides of the equation by 7, giving you x = 6. Therefore, there would be 6 marbles in each bag.