Final answer:
After reflecting point M located at (-3,7) across the z-axis, we get the point (3,7). Rotating this point 90° clockwise around the origin results in the point (7,-3). So, the y-coordinate of M” is -3.
Step-by-step explanation:
The student is asking about a transformation of a point in a coordinate plane following specific operations: a reflection across the z-axis and a subsequent 90° clockwise rotation about the origin.
To find the y-coordinate of the transformed point M” when M is at (-3,7), we first reflect M across the z-axis, which effectively changes the sign of the x-coordinate. Therefore, after reflection, point M becomes (3,7). Next, we rotate this point 90° clockwise about the origin. A 90° clockwise rotation swaps the coordinates and changes the sign of the new y-coordinate. Hence, after rotation, point M becomes (7,-3). The y-coordinate of point M” is -3.