To get the equation of the line when yu are given the x and y intercepts, you can use the two intercept form which is:
x/a + y/b = 1, where a and b are the x and y intercepts respectively.
Substituting 3 and -1/2 into the equation, we get
x/3 + y/(-1/2) = 1
x/3 - 2y = 1
x - 6y = 3
x - 6y - 3 = 0