N is M reflected across the y-axis; only the signs of the x-coordinates of M and N are different.
<u>Step-by-step explanation:</u>
In question no statements are available , below statements are the required one:
N is M reflected across the x-axis; only the signs of the x-coordinates of M and N are different: N is reflected over y-axis not x-axis so, this option itself is wrong!
N is M reflected across the x-axis; only the signs of the y-coordinates of M and N are different: N-M is reflected over y-axis not x-axis , so this option is also wrong.
N is M reflected across the y-axis; only the signs of the x-coordinates of M and N are different: N-M are reflected over y-axis correct and sign of only x co-ordinate is changed as Co-ordinates are and .Hence, this statement is correct!
N is M reflected across the y-axis; only the signs of the y-coordinates of M and N are different. N-M is reflected over y-axis , and sign of only x co-ordinate is changed not y . False statement.