Which of these ordered pairs could not be a dilation of (8, -4)?

For a dilation, both the X and Y values would need to keep the same ratio.

If you divide or multiply the X value by a number, you need to divide or multiply the Y value with the same number.

8/4 = 2, -4/4 = -1   First choice is a dilation.

Since we already know 8/4 = 2 and -4/4 = -1, then we can see that the 2nd choice is not a dilation.