A line passing through the point of intersection of `x + y = 4` and `x - y = 2` makes an angle `tan^-1 (3/4)` with the x-axis. It intersect the parabola `y^2 = 4(x-3)` at points `(x_1, y_1)` and `(x_2, y_2)` respectively. Then,`|x_1 - x_2|` is equal to