15. Jika 2x+3y = 13, 3x +2y = 12, ax + by = 13, dan

Jawaban:

2x + 3y = 13 |×3

3x + 2y = 12 |×2

——————-

6x + 9y=39

6x + 4y = 24

—————– –

5y = 15

y = 15/5

y = 3

2x + 3y = 13

2x + 3×3 = 13

2x + 9 =13

2x = 13-9

x=4:2

x = 2

2a + 3b =13

-2a + 3b = 5

—————– –

4a = 8

a = 8:4

a = 2

2a + 3b = 13

2 × 2 + 3b =13

4 + 3b =13

3b =9

b = 3

jadi 2a-b

2×2-3

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