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What is the solution to the following system?

-4y=8
x+3y-3z=-26
2x-5y+z=19

a) x = –53, y = –2, z = 7
b) x = –41, y = –2, z = –7
c) x = –11, y = –2, z = –7
d) x = 1, y = –2, z = 7

1 Answer

4 votes

Answer:

Option D (x = 1, y = -2, and z = 7).

Explanation:

This question can be solved using multiple ways. I will use the Gauss Jordan Method.

Step 1: Convert the system into the augmented matrix form:

• 0 -4 0 | 8

• 1 3 -3 | -26

• 2 -5 1 | 19

Step 2: Divide row 1 by -4 and switch row 1 and row 2:

• 1 3 -3 | -26

• 0 1 0 | -2

• 2 -5 1 | 19

Step 3: Multiply row 1 with -2 and add it in row 3:

• 1 3 -3 | -26

• 0 1 0 | -2

• 0 -11 7 | 71

Step 4: Multiply row 2 with 11 and add it in row 3:

• 1 3 -3 | -26

• 0 1 0 | -2

• 0 0 7 | 49

Step 5: Divide row 3 with 7:

• 1 3 -3 | -26

• 0 1 0 | -2

• 0 0 1 | 7

Step 6: It can be seen that when this updated augmented matrix is converted into a system, it comes out to be:

• x + 3y - 3z = -26

• y = -2

• z = 7

Step 7: Put z = 7 and y = -2 in equation 1:

• x + 3(-2) - 3(7) = -26

• x - 6 - 21 = -26

• x = 1.

So final answer is x = 1, y = -2, and z = 7. Therefore, Option D is the correct answer!!!

User Frops
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