diketahui sistem persamaan 3x+y-4z=20 x+2y+3z=14 3x+y+2z=11 nilai x,y,z berturut-turut adalah

>>EliMinaSi dan SubsTitusi

3x + y - 4z = 20
x + 2y + 3z = 14
3x + y + 2z = 11
Nilai dari x, y, dan z ?
*
-Eliminasi-
3x + y - 4z = 20
3x + y + 2z = 11 -
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- 6z = 9
z = - 3/2
*
3x + y - 4z = 20 |× 1
x + 2y + 3z = 14 |× 3
**************************
3x + y - 4z = 20
3x + 6y + 9z = 42 -
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- 5y - 13z = - 22
- 5y - 13×(-3/2) = - 22
- 5y + (39/2) = - 22
- 5y = -22 - (39/2)
- 5y = (-44-39)/2
-5y = -(83/2)
y = 83/10
*
x + 2y + 3z = 14
x + 2×(83/10) + 3×(-3/2) = 14
x + (83/5) - (9/2) = 14
x + (121/10) = 14
x = 14 - (121/10)
x = 19/10


Maka nilai x, y, z adalah
x = 19/10
y = 83/10
z = -3/2

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