Final answer:
To find the y-coordinate of B after a translation of 1-3.-5(x, y) is applied to square ABCD, subtract 3 from the original y-coordinate of B which is 2. The resulting y-coordinate is -1.
Step-by-step explanation:
To find the y-coordinate of B after a translation of 1-3.-5(x, y) is applied to square ABCD, we need to understand how translations affect coordinates. In a translation, each coordinate point is moved a certain distance horizontally and vertically. In this case, the x-coordinate is translated by 1 unit to the right, the y-coordinate is translated by -3 units downwards, and the z-coordinate (which is not relevant to this question) is translated by -5 units.
Since we are only concerned with the y-coordinate of point B, we can ignore the translations in the x and z directions. The original y-coordinate of B is 2, and the translation is -3 units downwards. Therefore, the y-coordinate of B after the translation is 2 - 3 = -1. Therefore, the correct answer is B. -5.