Provide a glimpse of some widely used matrix factorizations, some of which are discussed later in the text.
(QR Factorization) Suppose A + QR, where Q and R are n X n, R is invertible and upper triangular, and Q has the property that QTQ = I. Show that for each b in Rn, the equation Ax = b has a unique solution. What computations with Q and R will produce the solution?