9 more than twice a number is 840

The number (x) in: "9 more than twice a number is 840" is what we are solving here.

In other words, you are looking for a number (x) that if you multiply it by two (same as twice) and then add 9, you get 840.

To solve this, you first write the problem as an algebra equation as follows: 2x + 9 = 840

Then you solve the equation by subtracting 9 from both sides, and then divide both sides by 2. Here is the math to illustrate better:

2x + 9 = 840

2x + 9 - 9 = 840 - 9
2x = 831

2x/2 = 831/2
x = 415.5

Answer = 415.5

The answer above is correct, because twice 415.5 is 831, and 9 more than 831 is in fact 840.

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