math : write an equation that uses 18-?and 10+2.explain how to decide which numbers would make it true.

18 - x = 10 + 2

18 - 12 = x
6 = x

To write an equation using 18-? and 10+2, we will represent the unknown number with a variable, such as x.

The equation would be: 18 - x = 10 + 2.

To determine which numbers would make this equation true, we need to solve for x.

1. Start by simplifying both sides of the equation:
18 - x = 12

2. To isolate the variable x, subtract 18 from both sides of the equation:
-x = 12 - 18
-x = -6

3. To solve for x, multiply both sides of the equation by -1 to get rid of the negative sign:
x = 6

Therefore, the number that would make the equation true is 6. If you substitute 6 for the variable x in the original equation, it will hold true:
18 - 6 = 10 + 2.
12 = 12.