Answer:
Step-by-step explanation:
The given system of equation is
[tex]5x+2y=8\\1.25x+0.5y=2[/tex]
Mr. Brown multiplies the second equation by -4 and then he sums them up
[tex]5x+2y=8\\-5x-2y=-8\\\\0=0[/tex]
This result indicates that the sysmte has infinitely many solutions, because both equations represent the same line. Or you can see it as the lines are one on the other.
Therefore, the right answer here is D.