Answer:ion know
Step-by-step explanation:
Because it was reflected across the x axis, the distance between the two points is twice the distance of the old point from the x axis, and the distance from the old point from the x axis equals the distance from the new point to the x axis. The distance from the x axis is the absolute value of the x=y value. 7.5 is the y value, meaning the point is 7.5 units away from y=0, the x axis. The new point is twice this from the old point. 7.5 x 2 = 15. The new point is 15 units away from the old point.
ANSWER

EXPLANATION
The dimensions of a matrix is of the form:

The dimensions of the first matrix is

The dimensions of the second matrix is

Since the inner products are the same,the outer products give the dimensions of the product of the two matrices.

Therefore the dimensions of the product is a 2×2 matrix.