What happened to make plantation owners decide to use only slave labor for growing crops?

Agricultural cultivation of crops is a difficult process during few decades ago. Due to its difficulty and lack of machinery to simplify things, they plantation owners thought it wise to  use slaves in their farm. This is because, it is cheaper, cost less in terms of wages and minimal care for when they got sick when slaves are used compared to using their own people.

Explanation:

If you place a number in for x and solve this will help you to find y.

If you place a number in for x and solve this will help you to find y.

Step-by-step explanation: For example x=0 then we would do 2/3(0) -1= 0-1= y. Then you can go form there to find one of the y;'s then be able to do the other 4. :)