(* Define the spanning vectors *)
v1 = {2, -4, 3, -1};
v2 = {-3, 5, -5, -1};
v3 = {6, -2, 7, 5};
(* Define the basis vectors with unknown x *)
b1 = {1, 2, 0, 1};
b2 = {-3, 2, -3, 0};
x = {x1, x2, x3, x4};
(* Solve for x such that {b1, b2, x} spans the same space as {v1, v2, v3} *)
Solve[
LinearSolve[
Transpose[{v1, v2, v3}], {b1, b2, x}] == IdentityMatrix[3],
{x1, x2, x3, x4}
]
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