Answer with explanation:
A system of equation will have infinite number of solution
if both the equation of line are coincident.
6 x - y=b
-3 x + y = -3
Line, ax + by=c
p x + q y =r,
are said to be coincident , if

So,there is no real value of b for which , we can make the system of equation coincident or infinite umber of solutions.