Answer:
(1, -2)
Step-by-step explanation:
The dilation that has a center of (0, 0) means that you would multiply each number in your coordinate point by your given scale factor.
For your given point (2, -4) with a scale factor of 0.5:
2 times 0.5 = 1
-4 times 0.5 = -2
Therefore your new point will be (1, -2).