  Several widely-used textbooks lead the reader to believe that solving a
linear system of equations Ax = b by multiplying the vector b by a computed
inverse inv(A) is inaccurate. Virtually all other textbooks on numerical
analysis and numerical linear algebra advise against using computed inverses
without stating whether this is accurate or not. In fact, under reasonable
assumptions on how the inverse is computed, x = inv(A)*b is as accurate as the
solution computed by the best backward-stable solvers. This fact is not new,
but obviously obscure. We review the literature on the accuracy of this
computation and present a self-contained numerical analysis of it.
