In the given code snippet, there are two lines with multiple markers: the first line where the `addActionListener` method is called, and the third line where the variables are assigned values.
First line explanation:
- `btnCalculate.addActionListener(new ActionListener)()`: This line sets up an action listener for the `btnCalculate` button. An `ActionListener` interface is implemented and passed as an argument to the `addActionListener` method. The double parentheses `()` at the end of the line are incorrect and should be removed.
Corrected first line:
```java
btnCalculate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
// ActionListener code goes here
}
});
```
Third line explanation:
- `double recitation = Double.parse`: This line starts the assignment of the `recitation` variable, but it seems to be incomplete. It should be followed by `.Double(txtRecitation.getText());` to parse the value from the `txtRecitation` text field and assign it to `recitation`.
- The same pattern is followed for the `review`, `homework`, `participation`, `quizzes`, `prelim`, `midterm`, and `finals` variables.
Corrected third line:
```java
double recitation = Double.parseDouble(txtRecitation.getText());
double review = Double.parseDouble(txtReview.getText());
double homework = Double.parseDouble(txtHomework.getText());
double participation = Double.parseDouble(txtParticipation.getText());
double quizzes = Double.parseDouble(txtQuizzes.getText());
double prelim = Double.parseDouble(txtPrelim.getText());
double midterm = Double.parseDouble(txtMidterm.getText());
double finals = Double.parseDouble(txtFinals.getText());
```
After making these corrections, your code should work fine.