Solve the given inequality graphically:
3x+2yis less than equal to 150
x+4yis less than equal to 80
x is less than equal to 15
y is greater than equal to 0
x is greater than equal to 0.

The given inequations are:

​3x + 2y ≤ 150 … (1)

x + 4y ≤ 80 … (2)

x ≤ 15 … (3)

The graph of the lines, 3x + 2y = 150, x + 4y = 80, and x = 15, are drawn in the figure below.

Inequality (1) represents the region below the line, 3x + 2y = 150 (including the line 3x + 2y = 150). Inequality (2) represents the region below the line, x + 4y = 80 (including the line x + 4y = 80). Inequality (3) represents the region on the left hand side of the line, x = 15 (including the line x = 15).

Since x ≥ 0 and y ≥ 0, every point in the common shaded region in the first quadrant including the points on the respective lines and the axes represents the solution of the given system of linear inequalities.