Solve the following goal programming model graphically and by using the computer:

minimize P1d -

1 + P1d +

1 , P2d -

2 , P3d -

3 , 3P4d +

2 + 5P4d +

3 subject to x1 + x2 + d -

1 - d +

1 = 800 5x1 + d -

2 - d +

2 = 2,500 3x2 + d -

3 - d +

3 = 1,400 xj, d -

i , d +

i Ú 0 LO.1