Jawaban:

Ada di penjelasan

Penjelasan dengan langkah-langkah:

1. x - 2y = -8 --> x = -8 + 2y

2x + 3y = -9

2(-8 + 2y) + 3y = -9

-16 + 4y + 3y = -9

7y = -9 + 16

7y = 7

y = 7/7 = 1

x = -8 + 2y = -8 + 2 x 1 = -8 + 2 = -6

-2x + y = -2 x -6 + 1 = 12 + 1 = 13

2. umur ayah = x

umur anak perempuan = y

x - y = 49 ---> x = 49 + y

-5(x + y) = 41

-5(49 + y + y) = 41

-5(49 + 2y) = 41

-245 - 10y = 41

-10y = 41 + 245

-10y = 286

y = 286/-10 = -28.6 atau -29

x = 49-y = 49 -(-28.6) = 49 + 28.6 = 77.6 atau 78

3. alpukat = x

jambu = y

2x + y = 54000 --> y = 54000 - 2x

x + 2y = 45000

x + 2(54000 -2x) = 45000

x + 108000 - 4x = 45000

x - 4x = 45000 - 108000

-3x = -63000

x = -63000/-3 = 21000

y = 54000 - 2x21000 = 54000 - 42000 = 12000

2x + 3y = 2 x 21000 + 3 x 12000 = 42000 + 24000 = 66000

4. a. bunga mawar = x

bunga Lily = y

5x + 4y = 180500

4x + 3y = 140000

b. 5x + 4y = 180500 | x 4 = 20x + 16y = 722000

4x + 3y = 140000 | x 5 = 20x + 15y = 700000

------------------------------ -

y = 22000

5x + 4y = 180500

5x + 4 x 22000 = 180500

5x + 88000 = 180500

5x = 180500 - 88000

5x = 92500

x = 92500/5 = 18500

jadi harga bunga mawar Dan bunga Lily adalah Rp. 18.500,- Dan Rp. 22.000,-

c. x + 5y = 18500 + 5 x 22000 = 18500 + 110000 = 128500

5. karcis kelas I = x

karcis kelas II = y

x + y = 500 --> x = 500 - y

3000x + 6000y = 1950000

3x + 6y = 1950

3(500 - y) + 6y = 1950

1500 - 3y + 6y = 1950

3y = 1950 - 1500

3y = 450

y = 450/3 = 150

x = 500 - y = 500 - 150 = 350

jadi penonton kelas I Dan kelas II masing-masing sebanyak 350 orang Dan 150 orang