Perhatikan grafik berikut.

garis 1
2x + y = 6

garis 2
x + y = 4

2x + y = 6
x + y = 4
__________ -
x = 2

x + y = 4
2 + y = 4
y = 2

titik b ( 2,2)

titik A (4,0)
2X + 5Y
= 2(4) + 5(0)
= 8 + 0
= 8

titik B (2,2)
2X + 5Y
= 2(2) + 5(2)
= 4 + 10
= 14

titik C (0,6)
2X + 5Y
= 2(0) + 5(6)
= 0 + 30
= 30

jdi nilai minimum adalah 8 (b)