How do you changes 2 1/8 as a whole number

Well since there is a fraction involved, it can be a whole number and a decimal...so what you need to do is divide 1/8.  That should give you what?

Where m is the slope of the line and b is the y-intercept of the line, or the y-coordinate of the point at which the line crosses the y-axis. to write an equation in slope-intercept form, given a graph of that equation, pick two points on the line and use them to find the slope. this is the value of m in the equation.

Google it that might work