By Cramer's rule, the value of x_1 in Ax = b (where A is non-singular) is:
- $\det(A)/\det(A_1)$ (inverted)
- $\det(A_1)/\det(A)$ (correct ratio)
- $A_1 \cdot b$ (dot product)
- $\det(b)/\det(A)$ (b as matrix)
Show answer and 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.