How did the admission of these four states affect the voting power of slave states and free states in the u. s senate

The admission of these 4 states affected the voting power of slave and free states in the U.S. senate is because 3 of the states were free slave states and 1 of the states was a slave state. So that would probably mean that the free slave states would probably win against the slave states.

Explanation:

might be agreeing to participate ethically with other european nations in the slave trade

or notifying other european nations when taking possession   of african territories