diff --git a/education/software development/ECE1400/Chapter 9 Exercises.md b/education/software development/ECE1400/Chapter 9 Exercises.md
index 008bcdf..74bec6e 100644
--- a/education/software development/ECE1400/Chapter 9 Exercises.md	
+++ b/education/software development/ECE1400/Chapter 9 Exercises.md	
@@ -23,6 +23,18 @@ double triangle_area(double base, double height)
 > 2. Write a function `check(x, y, n)` that returns `1` if both `x` and `y` fall between zero and `n - 1` inclusive. The function should return 0 otherwise. Assume that `x`, `y`, and `n` are all of type int
 ```c
 int check(int x, int y, int n) {
-	if (x < 0)
+	int in_range = 1;
+	if (x < 0 || y < 0) {
+		in_range = 0;
+	}
+	if (x > n - 1 || y > n - 1) {
+		in_range = 0;
+	}
+
+	return in_range;
 }
-```
\ No newline at end of file
+```
+
+> 7. Suppose that function `f` has the following definition:
+> `int f(int a, int b) { ... }`
+> Which of the following statements are legal? Assume that `i` has type `int` and `x` has type `double`).