Find the measure of each marked angle. Assume the lines are parallel. \[ \begin{array}{l} x+1=\square \\ 9 x-21= \end{array} \] (Simplify your answers. Type an integer or a fraction.)

Step 1 ：The question is asking for the value of x that satisfies the two equations. The first equation is not complete, so I can't solve it. However, I can solve the second equation.

Step 2 ：The second equation is a simple linear equation, and I can solve it by adding 21 to both sides and then dividing by 9.

Step 3 ：\(x = x\)

Step 4 ：\(9x - 21 = 0\)

Step 5 ：Solving for x gives \(x = \frac{7}{3}\)

Step 6 ：Final Answer: The solution to the equation \(9x - 21 = 0\) is \(\boxed{\frac{7}{3}}\)