Answer:
The correct answer is (x, y) → (4x, 4y)
Explanation:
Notice that the vertice at (1, 5) is supposed to map onto the vertice at (4, 20) after the dilation.
To find the dilation factor, figure out what you can multiply x and y by in ΔABC to get the corresponding x and y in ΔDEF.
Notice that if you multiply 1 and 4 together, you get 4 and if you multiply 5 and 4 together, you get 20.
4 works with all the other vertices in ΔABC to get ΔDEF.
Therefore the correct answer is (x, y) → (4x, 4y).