Find the maximum value of x+y given that

x>=-3

y>=5x-9

3x+y<=15

X ≥ - 3

y ≥ 5x - 9

3x + y ≤ 15

3 (-3) + (5x - 9) ≤ 15

-9 + (5x - 9) ≤ 15

(-9 - 9) + 5x ≤ 15

-18 + 5x ≤ 15

+ 18 + 18

5x ≤ 33

5 5

x ≤ 6.6

y ≤ 5 (6.6) - 9

y ≤ 33 - 9

y ≤ 24

(x, y) ≤ (6.6, 24)