Can someone help me with number one please

Step-by-step explanation:

The center of dilation is at the point of intersection of the lines through an image point and the corresponding pre-image point.

Here, A and A' are both on the line x=5. C and C' are both on the line y=2, so the center of dilation is (x, y) = (5, 2).

__

The point A' is half as far from (5, 2) as the point A is, so the scale factor of the dilation is 1/2. (A' is 3 units down; A is 6 units down from the center of dilation.)