# How do you graph #a + b < 12# and #a - b >= 6#?

##### 1 Answer

Jul 20, 2015

Solve the system of 2 variables

a + b < 12

#### Explanation:

Let call a = y and b = x to avoid confusion.

(1) y < - x + 12

(2)

First, graph line y1 = - x + 12 by its 2 intercepts.

Make x = 0 -> y = 12. Make y = 0 -> x = 12.

The solution set of inequality (1) is the area **below** the line y1. Color or shade it.

Next graph line y2 = x + 6 by its 2 intercepts.

The solution set of (2) is the area **above** line y2. Color or shade it.

The compound solution set is the commonly shared area.

NOTE. The line y2 is included in the solution set

graph{-x + 12 [-10, 10, -5, 5]}

graph{x + 6 [-10, 10, -5, 5]}