What is the value of x in the equation 3x - 9 = 0?

To solve the equation 3x - 9 = 0, the first step is to isolate the variable x. Start by adding 9 to both sides of the equation, which results in 3x = 9. Next, to solve for x, divide both sides by 3. This gives us x = 9 / 3, which simplifies to x = 3.

Thus, the correct value of x is 3, as it satisfies the original equation when substituted back: 3(3) - 9 = 9 - 9 = 0. This confirms that the solution is valid.

It's essential to understand that the other options do not satisfy the equation when checked back. For instance, plugging in any value other than 3 will yield a result that does not equal zero, confirming that 3 is indeed the only solution.