Answer:
z(max) = 16
z(min) = -24
Explanation:
2x - y = 12 multiply by 2
4x - 2y = 24 (1)
4x + 2y = 0 add equations
8x = 24
x = 3
4(3) + 2y = 0
y = -6
so (3, -6) is a common point on these two lines
z = 2(3) + 5(-6) = -24
4x - 2y = 24 (1)
x + 2y = 6 add equations
5x = 30
x = 6
6 + 2y = 6
y = 0
so (6, 0) is a common point on these two lines
z = 2(6) + 5(0) = 12
4x + 2y = 0 multiply by -1
-4x - 2y = 0
x + 2y = 6 add equations
-3x = 6
x = -2
-2 + 2y = 6
y = 4
so (-2, 4) is a common point on these two lines
z = 2(-2) + 5(4) = 16