This question already has an answer here:
I'll have to ask an elementary level question about orbital motion and the mass/gravity that influences it.
In solar systems, the large mass of the sun pulls on the planets and we see the velocity of the outer planets traveling far slower than the inner planets because the mass in the rest of the solar system is far lower than the mass of the sun. If dark matter is spread throughout a galaxy, and not just at the center, would that not be like having massive planets in the outer part of a solar system, like a lot of jupiters that can have an effect on the planetary motion of the outer planets in the solar system? i.e. if there were a lot of jupiters in the outer regions of a solar system, would they cause the velocity of the outer planets to speed up, like we see in a galaxy with dark matter located throughout the galaxy?