If your draw the the three lines using the same grid, you will see that the three inequality share a region of a right triangle with the vertex (2,5), (2,3), and (6,3)
(2≤x≤6, and 3≤y≤5)
when x=6, y=3, C=2*6+5*3=27
when x=2, y=5, C=2*2+5*5=29
when x=2, y=3, C=2*2+5*3=19
the maximum value for C is 29
