Directions: Using the integers -9 to 9 (excluding 0) at most one time each, fill in the blanks to create two distinct perpendicular lines.

### Hint

### Hint

Why might we want to consider the relationship between the coefficients of x and y?

### Answer

### Answer

There are many solutions but not infinite

1 x + 2 y = 4

-6 x + 3 y = 5

2 x + 3 y = 9

-6 x + 4 y = 8

Any solution where the x and y coefficients swap and one is negative. Students will need to use multiples to avoid repeating values. The constant term can take any remaining value.

Source: Louise Pepper with answers from the students of Kings College Alicante, Spain