I need to determine a value of K for which the system has no solutions

2x-y=3

4x+ky=4

So,

y=-3/2x

k=10/y

x=-3/2

y=6

Therefore, K=-5/3

With all these values, I found that the system has a unique solution of K=-5/3 at the point (-3/2,-6)

How would I go about finding a value of K for which there is no solution? Is it just any value on the real number line that does not equal -5/3?