Question

What is the y-value that goes with an x-value of 5?

Answer 1

Answer: y = 7- 5x

Step-by Step Explanation: The variable x is multiplied by a larger value here; it's multiplied by 5. So I should expect that my y-values will grow fairly quickly. This means that I should expect a fairly "tall" graph.

First I'll do the T-chart.

T-chart

This equation is an example of a situation in which you will probably want to be particular about the x-values you pick. Because the x is multiplied by a relatively large value, the y-values grow quickly. For instance, you probably wouldn't want to use x = 10 or x = –7 as inputs. You could pick larger x-values if you wished, but your graph would very quickly get awfully tall.

I can see, from my T-chart, that my y-values are getting pretty big on either end (that is, in the positive numbers above the horizontal axis, and in the negative numbers below). I don't want to waste time computing points that will only serve to make my graph ridiculously large, so I'll quit with what I've got so far. But I'm glad I plotted more than just two points, because lines that start edging close to vertical can easily go wrong, if I'm not neat in my work.

Here's my graph:

y = 7 - 5x