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By Cramer's rule, the value of x_1 in Ax = b (where A is non-singular) is:
A$\det(A)/\det(A_1)$ (inverted)
B$\det(A_1)/\det(A)$ (correct ratio)
C$A_1 \cdot b$ (dot product)
D$\det(b)/\det(A)$ (b as matrix)
Answer & Solution
Correct answer: B. $\det(A_1)/\det(A)$ (correct ratio)
Cramer's rule: x_i = det(A_i)/det(A), where A_i is the matrix A with the i-th column replaced by b. Requires det(A) ≠ 0 for unique solution.
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