systems have no solution if they have the same slope, but different y-intercepts.
3/4x - 1/2y = 12, y = 2(3/4x - 12) = 3/2x - 24
ax - by = 9, y = (ax-9)/b, = ax/b -9/b
for the slopes to be the same, following must be true:
ax/b = 3/2x
a/b = 3/2
Correct answer is C
