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]}