Find the missing number in the proportion.

12 6
___=____
x+7 7

To find the missing number, we can use the property of proportions where the cross-products are equal.

We can set up the proportion as follows:

12/(x+7) = 6/7

Now we can solve for x. To do this, we can cross-multiply:

12 * 7 = 6 * (x+7)

84 = 6x + 42

Next, we can subtract 42 from both sides:

84 - 42 = 6x

42 = 6x

Finally, we can divide both sides by 6 to solve for x:

42/6 = x

7 = x

Therefore, the missing number in the proportion is x = 7.