If the arithmetic mean of x, x+3, x+6, x+9, and x+12 is 10, the x =

The arithmetic mean of a set of numbers is calculated by adding all the numbers together and then dividing by the count of numbers.

In this case, the numbers are x, x+3, x+6, x+9, and x+12.

Step 1: Add the numbers together: x + (x+3) + (x+6) + (x+9) + (x+12) = 5x + 30

Step 2: Set this equal to the mean times the count of numbers (which is 5 in this case), because the mean is the total divided by the count: 5x + 30 = 10 * 5

Step 3: Simplify the equation: 5x + 30 = 50

Step 4: Subtract 30 from both sides to solve for x: 5x = 20

Step 5: Divide both sides by 5: x = 4

So, if the arithmetic mean of x, x+3, x+6, x+9, and x+12 is 10, then x equals 4.