Why did black people work at the cotton club

Because they can.

Step-by-step explanation:

they were bought and brought in as slaves to work the giant farm lands as help. for room and board and food they did the labor by picking the cotton

2·(a^2 + b^2) = (a + b)^2

2·a^2 + 2·b^2 = a^2 + 2·a·b + b^2

a^2 + b^2 = 2·a·b

a^2 - 2·a·b + b^2  = 0

(a - b)^2 = 0

a = b