In order for a line to intersect the x-axis, it has to pass through y=0
So set the equation equal to zero:
-3/2x + 6 = 0
solve for x
-3/2x = -6 subtract each side by 6
-3x = -12 divide each side by -3
x=4
thus the coordinates of the point it intersects the x-axis is (4, 0)