Slope or Gradient of a Line

The slope or gradient of a line is a number that describes both the direction and the steepness of the line. Given a line represented by y = mx + b, it is said that m represents its slope. This form of a line's equation is called the slope-intercept form, because b can be interpreted as the y-intercept of the line, that is, the y-coordinate where the line intersects the y-axis.

Created with GeoGebra by Vitor Nunes

Interactivity

Change the value of the m and b parameter to see what happens to the line.

See what happens to the slope of the line when the variable m assumes a negative value.

Note that when the value of m is zero, the line becomes parallel to the x-axis.

Information

When a line rises from left to right, the slope is a positive number. When a line falls from left to right, the slope is a negative number. The x-axis or any line parallel to the x-axis has a slope of zero. The y-axis or any line parallel to the y-axis has no defined slope.