Question

DEF with vertices D(2, 5), E(6, 4), and F(3, 3), is reflected across the line y=x

. A student determined one of the vertices on the image to be (2, –5). Evaluate the student’s answer.

Answer 1

The student's answer is wrong. When a point (a, b) is reflected across the line y=x, the coordinates of the new point is reversed to (b, a). So D(2, 5) would become (5, 2), E(6, 4) would become (4, 6), and F(3, 3) is still (3, 3). None of the new points is (2, -5).