The binomials needed to be factored are examples of perfect square binomials, so the factors should contain the square root of the expressions inside the binomial. The pairs are, [tex]16 x^{2} -1 and (4x-1)(4x+1)[/tex], [tex]4 x^{2} -9 and (2x+3)(2x-3)[/tex], [tex]4 x^{2} -1 and (2x-1)(2x+1)[/tex], the last one is a bit tricky because its factors still has a common factor that can be taken out and it is, [tex]16 x^{2} -4 and 4(2x+1)(2x-1)[/tex]
