m is called the “slope,” or sometimes “gradient. “[2] X Research source Slope is defined as rise over run, or the change in y over the change in x. b is defined as the “y-intercept. " The y-intercept is the point at which the line crosses the Y-axis. [3] X Research source x and y are both variables. You can solve for a specific value of x, for example, if you have a y point and know the m and b values. x, however, is never merely one value: its value changes as you go up or down the line.
For example, let’s take the equation y = 1/4x + 5. Since the last number is b, we know that b equals 5. Go 5 points up on the Y-axis and mark the point. This is where your straight line will pass through the Y-axis.
The first number (numerator) is the rise in rise over run. It’s how far the line travels up, or vertically. The second number (denominator) is the run in rise over run. It’s how far the line travels to the side, or horizontally. For example: A 4/1 slope travels 4 points up for every 1 point over. A -2/1 slope travels 2 points down for every 1 point over. A 1/5 slope travels 1 point up for every 5 points over.
For example, using the illustration above, you can see that for every 1 point the line rises up, it travels 4 to the right. That’s because the slope of the line is 1/4. You extend the line indefinitely along both sides, continuing to use rise over run to graph the line. Whereas positive-value slopes travel upward, negative-value slopes travel downward. A slope of -1/4, for example, would travel down 1 point for every 4 points it travels to the right.
