Solve the absolute value equation

|10n + 1|+ 20=9
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
• A. The solution set is ____
• B. The solution set is no solution
(Type an integer or a simplified fraction. Use a comma to separate answers as needed.)

To solve the absolute value equation |10n + 1| + 20 = 9, we isolate the absolute value term by subtracting 20 from both sides:

|10n + 1| + 20 - 20 = 9 - 20

|10n + 1| = -11

Absolute value can only be equal to a non-negative value, so -11 is not a possible solution. Thus, the solution set is no solution.