Which of the following describes how to graph the line whose equation is y = x - 1?

In order to graph an equation of the line, you only need to know two point. This can be achieved by taking the x- and y-intercepts. 

x-intercept:let y = 0

0 = x - 1
x = 1 (plot 1 on the positive x line)

y-intercept: let x=0

y = 0 - 1 = -1 (plot -1 on the negative y line)

Connect this two points and you obtain a line.