[tex]a) {x}^{2} - 1 = (x - 1)(x + 1)[/tex]
[tex]b) {x}^{2} - 4 = (x - 2)(x + 2)[/tex]
[tex]c) {x}^{2} - 9 = (x - 3)(x + 3)[/tex]
[tex]d) {x}^{2} - 16 = (x - 4)(x + 4)[/tex]
[tex]e) {x}^{2} - 25 = (x - 5)(x + 5)[/tex]
[tex]f) {x}^{2} - 36 = (x - 6)(x + 6)[/tex]
[tex]g) {x}^{2} - 49 = (x - 7)(x + 7)[/tex]
[tex]h) {x}^{2} - 64 = (x - 8)(x + 8)[/tex]
[tex]i) {x}^{2} - 81 = (x - 9)(x + 9)[/tex]