Mohon bantuin sist dan gan. Dan cara penyelesaiannya

Kelas 11 Matematika
Bab Program Linear

x + 2y = 8
x = 8 - 2y

2x + y = 10
2 (8 - 2y) + y = 10
16 - 4y + y = 10
-3y = 10 - 16
y = -6/-3
y = 2

x = 8 - 2y
x = 8 - 2 . 2
x = 4

Titik potong = (4, 2)

x + 2y = 8 → (8,0) dan (0, 4)
2x + y = 10 → (5, 0) dan (0, 10)

z = 3x + 4y

z(4, 2) = 3 . 4 + 4 . 2
z(4, 2) = 12 + 8
z(4, 2) = 20

z(0, 4) = 3 . 0 + 4 . 4
z(0, 4) = 16

z(5, 0) = 3 . 5 + 4 . 0
z(5, 0) = 15

Nilai maksimum = 20