A point A is reflected in the origin (M0) and then in y-axis (My) after which the new point is A'. Which single transformation maps A onto A' ?
Mx
Let point A be (x, y)
Image of A(x , y) when reflected in the origin is (-x, -y)
Image of A(-x , -y) when reflected in the y axis (x, -y)
The operation Mx on A(x, y) will result in (x, -y) which is same as M0,My.