Consider the following linear system.x + 2y - 3z = a2x + 3y + 3z = b5x...
(AB) = (1 2 -3 a 2 3 3 b 5 9 - 6 c)
(R2 - 2R1) ; (R3-5R1)
≈ (1 2 - 3 a 0 -1 9 b - 2a 0 -1 9 c - 5a)
(R3 - R2)
≈ (1 2 - 3 a 0 - 1 9 b - 2a 0 0 0 (c - b - 3a))
(c - b - 3a)
3a + b - c = 0
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Consider the following linear system.x + 2y - 3z = a2x + 3y + 3z = b5x...
Explanation:
Consistent System:
- A linear system is consistent if it has at least one solution.
- In other words, the system has a solution when the number of equations is equal to or less than the number of unknown variables.
Given System:
- x + 2y - 3z = a
- 2x + 3y + 3z = b
- 5x + 9y - 6z = c
Rewriting the System:
- We can rewrite the given system in matrix form as: AX = B, where:
A = [[1, 2, -3], [2, 3, 3], [5, 9, -6]], X = [[x], [y], [z]], and B = [[a], [b], [c]].
Consistency Condition:
- For the system to be consistent, the determinant of matrix A must be equal to the determinant of the augmented matrix [A|B].
- The system is consistent if det(A) = det([A|B]).
Determinant Calculation:
- det(A) = -3(3*9 - 3*9) - 2(2*9 - 3*5) + 5(2*3 - 3*3) = -27 + 6 + 15 = -6
- det([A|B]) = -3(3(c) - 3(b)) - 2(2(c) - 3(a)) + 5(2(b) - 3(a))
= -3(3c - 3b) - 2(2c - 3a) + 5(2b - 3a)
= -9c + 9b - 4c + 6a + 10b - 15a
= 6a + 19b - 9c
Consistency Condition (cont.):
- For the system to be consistent, det(A) = det([A|B]) must hold true.
- Therefore, -6 = 6a + 19b - 9c
- Simplifying, we get 6a + 19b - 9c = -6
- Comparing with the given options, we find that 3a + b - c = 0, which matches the consistency condition.
Therefore, the correct answer is option B) 3a + b - c = 0.