Bantu ya

Jawaban:

1.) y = x + 4

z = x + 17

x + x + 4 + x + 17 = 45

3x + 21 = 45

3x = 24

x = 9

x+4=y

9+4=y

y = 13

z – 17 = x

z – 17 = 9

z = 26

2.) 3x + 4y – 5z = 12 dikali 2

6x + 8y – 10z = 24

6x + 2y – 3z = 17

—————————– –

6y – 7z = 7

2x + 5y – z = 17 dikali 3

6x + 15y – 3z = 51

6x + 2y – 3z = 17

—————————– –

13y = 34

y = 34/13 = 2 8/13

6y – 7z = 7

6(34/13) – 7z = 7

204/13 – 7z = 7 dikali 13

204 – 91z = 91

-91z = -113

z = 113/91 = 1 22/91

2x + 5(34/13) – (113/91) = 17

2x + 170/13 – 113/91 = 17

2x + 1190/91 – 113/91 = 17

2x + 1077/91 = 17 dikali dengan 91

182x + 1077 = 1547

182x = 470

x = 470/182 = 235/91 = 2 53/91