According to economists, this episode of great recession was resulted from a sudden busting of house bubble in US, where the house bubble was caused by rapid growth of improper regulation on sub-prime mortgages (Merriam 2009; Wang 2009; Whitney 2007).
When working with equations that have two variables, the coordinate plane is an important tool. It's a way to draw pictures of equations that makes them easier to understand. To create a coordinate plane, start with a sheet of graph or grid paper. Next, draw a horizontal line.
To graph an equation on the coordinate plane, find the coordinate by giving a value to one variable and solving the resulting equation for the other value. Repeat this process to find other coordinates. (When giving a value for one variable, you could start with 0, then try 1, and so on.) Then graph the solutions.