Respuesta :
General Idea:
Reflection Rules:
The reflection of the point (x,y) across the x-axis is the point (x,-y).
The reflection of the point (x,y) across the y-axis is the point (-x,y).
The reflection of the point (x,y) across the line is the point (y, x)
Rotation Rules:
The 90 degree counterclockwise rotation about the origin of a point (x, y) is the point (-y, x)
The 180 degree counterclockwise rotation about the origin of a point (x, y) is the point (-x, -y)
The 270 degree counterclockwise rotation about the origin of a point (x, y) is the point (y, -x)
The 90 degree clockwise rotation about the origin of a point (x, y) is the point (y, -x)
The 180 degree clockwise rotation about the origin of a point (x, y) is the point (-x, -y)
The 270 degree clockwise rotation about the origin of a point (x, y) is the point (-y, x)
Applying the concept:
Say if we have a point (x, y)
After we "Rotate 180 degrees counterclockwise" the point becomes (-x, -y) and after we perform the transformation "rotate 90 degrees clockwise" the point becomes (-y, x). So transformation described in Option A WILL NOT result in an image that maps onto itself.
After we "Reflect across a line" the point becomes (y, x) and after we "then reflect again across the line" the point (y, x) becomes (x, y). So transformation described in Option B WILL result in an image that maps onto itself.
After we "rotate 270 degrees counterclockwise" the point becomes (y, -x) and after we " translate 5 units left" the point (y, -x) becomes (y - 5, -x). So transformation described in Option C WILL NOT result in an image that maps onto itself.
After we "reflect across the x-axis" the point becomes (x, -y) and after we "reflect across the y-axis" the point (x, -y) becomes (-x, -y). So transformation described in Option D WILL NOT result in an image that maps onto itself.
Conclusion:
The answer is option B. The following transformation of "reflect across a line and then reflect again across the line" will result in an image that maps onto itself.
