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Solve the system by elimination 5x - 3y + 4z = - 16-4x + 2y - 3z = 12 - x + 5y + 7z =32 X = Y = Z =

User Cala
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1 Answer

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Total Equations are 3:

5x-3y+4z=-16→(1)

-4x+2y-3z=12→(2)

-x+5y+7z=32→(3)

Step 1: Select the equations (1) and (3), and eliminate the variable x.

(5x - 3y + 4z = -16) x 1 → 5x - 3y + 4z = -16

( -x + 5y + 7z = 32) x 5 → + -5x + 25y+ 35z = 160

22y+ 39z = 144 → (4)

Step 2: Select the equations (2) and (3), and eliminate the variable x.

( -4x + 2y - 3z = 12) x 1 → -4x + 2y - 3z = 12

( -x + 5y + 7z = 32) x 4 → - -4x + 20y + 28z = 128

- 18y - 31z = -116→ (5)

Step 3: Select the equations (4) and (5), and eliminate the variable y.

(22y + 39z = 144) x 9 →198y + 351z = 1296

(-18y - 31z = -116) x 11 → + -198y - 341z = -1276

10z = 20

10z/10 = 20/10

z = 2

Therefore, z = 2.

For y, plug-in z = 2 in equation 5.

-18y - 31z = -116

-18y - 31(2) = -116

-18y + 64 = -116

-18y = -116 + 62

-18y = -54

-18y/-18 = -54/-18

y = 3

Therefore, y = 3.

For x, plug-in y = 3 and z = 2 in Equation 3.

-x + 5y + 7z = 32

-x + 5(3) + 7(2) = 32

-x + 15 + 14 = 32

-x + 29 = 32

-x = 32 - 29

-x = 3

-x/-1 = 3/-1

x = -3

Therefore, x = -3.

In Summary:

x = -3

y = 3

z = 2

User Fyjham
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