Final answer:
To solve the equation, we can first double the unknown number, subtract two, and set it equal to nine. Then, we can solve for the unknown number using algebraic operations.
Step-by-step explanation:
To form an equation for the unknown number, let's call the number x. According to the problem, when you double the number, you get 2x. And when you subtract two from that, you get 2x-2. We know that this value is equal to nine, so we can write the equation as:
2x-2 = 9
To solve for x, we can start by adding 2 to both sides of the equation:
2x = 9 + 2
2x = 11
Finally, divide both sides of the equation by 2:
x = 11/2 = 5.5
Therefore, the unknown number is 5.5.
Learn more about Solving equations involving unknown numbers