STEP - BY - STEP EXPLANATION
What to find?
Description of a figure and its image match the transformation.
Given:
(x, y)→(x, 3y)
Note that;
If a function is stretched horizontally by a factor "a" , then a will be multiplied by x.
If a function is stretched vertically by a factor "a", then a will be multiplied by y.
Hence, since 3 is multiplied by y, we can conclude that it is a vertical stretch.
Therefore, the transformation description will be; the figure and its image are neither similar nor congruent and the image has been stretched vertically.
ANSWER
The figure and its image are neither similar nor congruent and the image has been stretched vertically.