solve the system of inequalities x+2y>= 20 and 3x+y<=15

Given

x+2y>=20

3x+y<=15

The graph of the lines, x +2 y= 20 and 3x + y = 15, are drawn in the figure below.
Inequality (1) represents the region above the line, x +2 y= 20 (including the line x +2 y= 20), and inequality (2) represents the region below the line, 3x + y = 15 (including
the line 3x + y = 15).
Hence, the solution of the given system of linear inequalities is represented by the
common shaded region including the points on the respective lines as follows