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Jika 2 x − y = − 1 , 3 x − 2 y = − 3 , a x − 2 y = 4 b , dan 4 x − a y = 2 b , maka a + b = ....

Jika  dan , maka a + b = .... 

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M. Robo

Master Teacher

Jawaban terverifikasi

Jawaban

a + b = 2 + (-1) = 1.

a + b = 2 + (-1) = 1.

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Pembahasan

Kemudian a(1) - 2(3) = 4b a - 6 = 4b a - 4b = 6 a = 4b + 6 ..........(1) dan 4(1) - a(3) = 2b 4 - 3a = 2b 3a + 2b = 4 ..........(2) Substitusi persamaan (1) ke persamaan (2) 3(4b + 6) + 2b = 4 12b + 18 + 2b = 4 14b = -14 b = -1 Lalu a = 4(-1) + 6 = 2 Jadi, a + b = 2 + (-1) = 1.

begin mathsize 14px style table row cell 2 x minus y equals negative 1 end cell cell left parenthesis cross times 2 right parenthesis end cell cell 4 x minus 2 y equals negative 2 end cell blank row cell 3 x minus 2 y equals negative 3 end cell cell open parentheses cross times 1 close parentheses end cell cell bottom enclose 3 x minus 2 y equals negative 3 end enclose end cell minus end table space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space x equals 1 space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space y equals 3 end style

Kemudian
a(1) - 2(3) = 4b
a - 6 = 4b
a - 4b = 6
a = 4b + 6 ..........(1)

dan
4(1) - a(3) = 2b
4 - 3a = 2b
3a + 2b = 4 ..........(2)

Substitusi persamaan (1) ke persamaan (2)
3(4b + 6) + 2b = 4
12b + 18 + 2b = 4
14b = -14
b = -1

Lalu a = 4(-1) + 6 = 2

Jadi, a + b = 2 + (-1) = 1.

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