To solve for x in the equation 9-x=11, you need to isolate x on one side of the equation.
One way to do this is to subtract 9 from both sides of the equation:
9 - x - 9 = 11 - 9
Simplifying the left side gives:
-x = 2
To isolate x, we can multiply both sides by -1:
-x * (-1) = 2 * (-1)
This gives:
x = -2
Therefore, the solution to the equation 9-x=11 is x = -2.