graph the inequality on a plane

3x+4y is less then or equal to 12

Given: 3x + 4y <= 12.

Graph: 3x + 4y = 12, the boundary line,

Select values of x and calculate the
corresponding value of:

(0 , 3) , (2 , 1.5) , (4 , 0).

Since there is an = sign in your inequality, all points on the boundary
line should satisfy the inequality.
The < sign means that all points below the boundry line should also
satisfy the inequality.