General definitions

General definitions

 The non-constant term in the linear function y = αx indicates that the line passes from the beginning of the axes. The existence of the fixed term in the linear function y = αx + β indicates that the line intersects the vertical axis.≤ α <0 and β <0 in the linear function y = αx + β indicates that the line crosses the vertical negative half-axle and forms an angle with the horizontal axis greater than 90 degrees. a> 0 and β <0 on the linear function y = αx + β indicates that the line crosses the vertical negative half-axis and forms an angle with the horizontal axis less than 90 degrees.