How do you graph #y=4x-7#?
1 Answer
There are several ways, but the easiest is probably to start at a point (the y-intercept) and follow the slope.
Explanation:
You know that when x = 0, y = -7 (because y = 4(0)-7 = -7, or you just know the fact that the constant number shows the y-value of the y-intercept). Therefore, you can plot that point on the graph:
Then, let's use the slope of the line in the graph as well. The slope represents the "rise over run", or change in x over change in y. Therefore, if the slope is some number, the y value changes that number of units every time the x increases by one. Using this knowledge, we can simply move over one unit, then move up four units (because the slope is 4), and plot another point:
After plotting only two points, you already have enough information to make the line. Simply draw a line that goes through the two points, and you're done!
(Note that if you continue this pattern - moving right one, up four, and drawing a point - then that point will also be on the line:
)
(Note: You can also plug in any two different x values into the equation, find the y values, draw them on the graph, and then draw a line between them.)
