What is wrong with the following method call?

int displayValue (x);

It's not a call, but a declaration (also incorrect).

For a call, you'd have something like
y = displayValue (x);

The issue with the following method call is the use of parentheses when declaring the parameter type. In Java, when declaring a method, you do not need to include parentheses around the parameter type. Instead, you should just specify the parameter type and name.

To correct the method call, you should remove the parentheses around the parameter type, like this:

int displayValue (x);

Additionally, the method declaration should be followed by a method body enclosed in braces {}. So, assuming you have a method called "displayValue" that takes an int parameter named "x", the correct method call would be:

int result = displayValue(x); // Assuming you want to assign the returned value to a variable.