Prove that if B is obtained from A by performing a sequence of elementary row operations, then there is a second sequence of elementary row operations, which when applied to B recovers A.

Evaluating Limits Algebraically EXAMPLE 1 multiplying by the conjugate lim( 1 − 22 ) x→1 x−1 x −1 Multiply by the conjugate: 1(x+1) 2 lim (x−1)(x+1) x −1 x→1 lim x21−2 x→1 x −1 x−1 lim x −1 x→1 lim 1 = 1 x→1 x+1 2 EXAMPLE 2 1 1 x→0( x ) =x0 Another ex 1 2 x→c( x ) x± ∞ limf(x) = f(c) if f is continuous...