a certain number x is decreased by 15 is equal to twice the number increased by 3. what is the correct mathematical expression?

x - 15 = 2x + 3

Let x be the certain number.

The expression "a certain number x is decreased by 15" can be written as x - 15.

The expression "twice the number increased by 3" can be written as 2x + 3.

Therefore, the correct mathematical expression for the given statement is: x - 15 = 2x + 3.

To represent the given situation mathematically, we can break it down:

Let's assume the number x.
The expression "a certain number x is decreased by 15" can be written as x - 15.
The expression "twice the number increased by 3" can be written as 2x + 3.

Putting it all together, we can form the equation:

x - 15 = 2x + 3

This equation represents the relationship between the number x, its decrease by 15, and twice the number increased by 3.