T: R^2 → R^2 first performs a horizontal shear that transforms e2 into e2 - 2e1 (leaving ei unchanged) and then reflects points through the line x2= -x1.

“exterior angles of triangles. an exterior (or external) angle is the angle between one side of a triangle and the extension of an adjacent side. try this drag the orange dots on any vertex to reshape the triangle.” look to get to the answer i explained what it means and other things i hope it you .