solve the following system of inequalities graphically

Question

3x+2y<150, x+4y<80, x<80,x>0,y>0

Answer 1

draw each line. Then shade the area below the two slanting lines, above the x-axis, and between the y-axis and the vertical line at x=80.

The solution is the part where all the shaded areas intersect.

A good start is shown here:

http://www.wolframalpha.com/input/?i=solve+3x%2B2y%3C150%2C+x%2B4y%3C80