Question

Solve the equations
9x + 2y + 5z = 28
4x + 3y + 3z = 19
18x - 5y + z = 29.
Please give step by step solution .
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Answer 1

Answer:

9x + 2y + 5z = 28 ⇒1

4x + 3y + 3z = 19⇒ 2

18x - 5y + z = 29 ⇒ 3

1 ×4⇒

36x+8y+20z=112

2 × 9 ⇒

36x+27y+27z =171

3 ×2⇒

36x-10y+2z=58

36x+8y+20z-(36x+27y+27z)-(36x-10y+2z)=112- 171 - 58

-36x - 9y - 9z = -117

-9(4x+y+z)/-9= -117/-9

⇔4x+y+z=13