Is y equals x-1a funcation or non-funcation?

Answer 1

When you are determining whether an equation is a function or not, you have several options for doing so. The first is to graph it. From there, you can use the vertical line test (if at any point on the graph a vertical line will touch no more than one point, then it is a function). You can also make a chart that lists enough points on the graph that it will give you an idea of whether or not it is a function. You third option is to compare it to other, simpler functions: in this case, y = x. You know that y = x is definitely a function, and that is is a straight line going through the origin and rotated 45 degrees clockwise from the y-axis. Subtracting one from this function only moves it down one unit so the line will cross at y = -1 instead of y = 0. The negative one acts as the "b" since this equation is in y = mx + b, form, so that is where it crossed the y-axis. It is, then, a function.