The ordered pair (0,4) is a soultion of which system

This question is asking you to substitute 0 for X and 5 for y in both equations. If the right hand value is equal to the left hand value after making the substitution, the answer is "yes". Otherwise, the answer is "no".

Substitute 0 for x and 5 for y in the first equation and then the second equation. Since 0 + 5 = 5 and - 5*0 + 2*5 = 10 the answer