Knowing y=kx-3, we can determine that the coordinate of a point on the Y axis of this function image is (0, -3), and the distance from this point to the origin is 3, and because the area formula of a right triangle is that two right angles are multiplied by two, the coordinate of a point on the X axis of this function image is (6,0) or (-6,0).

Next, we need to discuss it in categories.

When the coordinate of this function image on the X axis is (6,0), it can be concluded that when y=0, X is 6, and it can be listed that 6k-3=0, then k=0.5, and the analytical formula y=0.5x-3 is obtained.

When the coordinate of this function image on the X axis is (-6,0), it can be concluded that when y=0, X is-6, and it can be listed that -6k-3=0, then k=-0.5, and the analytical formula y=-0.5x-3 is obtained.

I won't write if you answer, I know.

By the way, I'm a junior, maybe it's not a standard format, but the idea has been given and I should be able to make it.

Please, you must adopt it.