Which system has a unique solution?
Ax + y = 4, 2x + 2y = 8
Bx + y = 3, x − y = 1
Cx + y = 5, x + y = 7
Dx + y = 1, 2x + 2y = 2
Answer & Solution
Correct answer: B. x + y = 3, x − y = 1
Option C has a₁/a₂ = 1/1 and b₁/b₂ = 1/−1, not equal. Lines intersect, unique solution. The others are parallel or coincident.
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