What is slope?

Incline, also known as slope, is the angle formed between a line or curve and the horizontal axis. The angle formed with the vertical axis is called elevation. The incline of a curved line is expressed as either positive or negative, depending on the angle formed with the horizontal axis. A negative incline indicates that the line is inclined downward to the left of the horizontal axis, while a positive incline indicates that the line is inclined upward to the right of the horizontal axis.