4. y = -4 and 7y = -28

this is true

Explanation:

y = -4

7y = -28 (eqn 2)

put y = -4 in eqn 2,

7*(-4) = -28

-28 = -28

There's your answer.

Hope this helps, and please mark me brainliest if it does!

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