If x + 5 = 10, what is the value of x?

To find the value of x in the equation x + 5 = 10, you need to isolate x on one side of the equation. This can be achieved by subtracting 5 from both sides.

Starting with the original equation:

x + 5 = 10

Subtracting 5 from both sides gives:

x + 5 - 5 = 10 - 5

This simplifies to:

x = 5

Therefore, the value of x is 5.

This solution follows basic algebraic principles, where one of the key skills is to manipulate equations to find unknown variables. The other options do not satisfy the equation when substituted for x. For instance, substituting 0, 10, or 15 would not hold true as these do not equal 10 when you add 5 to them. Thus, the correct answer is 5.