tolong jawab pertanyaan berikut, dengan cara

........................ Roti 1 (x) ....... Roti 2 (y) .........
Tepung ....... 50 gram ....... 30 gram .......... 15 kg = 15.000 gram
Mentega .... 25 gram ........ 60 gram ......... 16 kg = 16.000 gram
Harga .......... 3.000 ............ 4.000 ............. ????

Model matematika
1) tepung : 50x + 30y ≤ 15.000
=> 5x + 3y = 1.500
=> x = 0 => y = 500 ==> (0, 500)
=> y = 0 => x = 300 ==> (300, 0)

2) mentega : 25x + 60y ≤ 16.000
=> 5x + 12y ≤ 3.200
=> x = 0 => y = 800/3 ==> (0, 800/3)
=> y = 0 => x = 640 ==> (640, 0)

Fungsi Sasaran : f(x, y) = 3.000x + 4.000y

Titik potong kedua garis :
5x + 3y = 1.500
5x + 12y = 3.200
------------------------- --
...... -9y = -1.700 ==> y = 1.700/9
5x + 3y = 1500
=> 5x + 3(1700/9) = 1500
=> 5x + 1700/3 = 1500
=> 5x = 2800/3
=> x = 560/3

Titik sudut yang diperoleh : (0, 800/3), (300,0) dan (560/3, 1700/9)
Substitusi ke f(x, y) = 3000x + 4000y
(0, 800/3) => 3000(0) + 4000(800/3) = 1.066.666,67
(300, 0) => 3000(300) + 4000(0) = 900.000
(560/3, 1700/9) => (3000(560/3) + 4000(1700/9) = 1.315.555,56

Jadi pendapatan maksimumnya 1.315.555,56 dengan menjual roti 1 sebanyak 560/3 dan roti 2 = 1700/9

Angkanya kok tidak bagus