How do you know if you need to shade above or below the line?

1 Answer
Mar 20, 2018

The direction of the inequality will tell you this information.

Explanation:

Example: #y >= 2x+3#

You would draw the line #y = 2x+3# and shade above the line, since #y# is also greater than # 2x+3#.

graph{y>=2x+3 [-10, 10, -5, 5]}

Example: #y < 1/2x-2#

You would draw the line #y=1/2x-2# as a dashed line, then shade below the line since #y# is less than #1/2x-2#.

graph{y<1/2x-2 [-10, 10, -5, 5]}