Tolong no.9,10,11,12 sama caranya yaa☝

10.
ayam = x
itik = y
4x + 2y = 110000 <=> 2x + y = 55000 <=> y = 55000 – 2x …pers. 1
5x + 3y = 75000 … pers. 2
masukkan pers.1 ke pers. 2
5x + 3(55000 – 2x) = 75000
5x + 165000 – 6x = 75000
-x = -90000
x = 90000 (harga seekor ayam)

11. 
x + 3y = 18 … pers. 1
4x + 2y = 12 <=> 2x + y = 6 <=> y = 6 -2x …pers. 2
masukkan pers. 2 ke pers. 1
x + 3(6 – 2x) = 18
x + 18 – 6x = 18
-5x = 0
x = 0
masukkan x = 0 ke salah satu persamaan;
x+3y = 18
0 + 3y = 18
y = 6

x + y = 0 + 6 = 6