17. How did the African economy benefit from the slave trade?

he Transatlantic slave trade radically impaired Africa's potential to develop economically and maintain its social and political stability. The arrival of Europeans on the West African Coast and their establishment of slave ports in various parts of the continent triggered a continuous process of exploitation of Africa's human resources, labor, and commodities. This exploitative commerce influenced the African political and religious aristocracies, the warrior classes and the biracial elite, who made small gains from the slave trade, to participate in the oppression of their own people. The Europeans, on the other hand, greatly benefited from the Atlantic trade, since it allowed them to amass the raw materials that fed the Industrial Revolution to the detriment of African societies whose capacity to transform their modes of production into a viable entrepreneurial economy was severely halted.

Explanation:

the perimeter of a triangle is 69 cm. side a is 5 cm shorter than side b. side c is twice as long as side a. find the length of each side. i need to know how to do it in 2 equations.  

equations:

a = b-5

c = 2a

a + b + c = 69