[tex] {(x + 2)}^{2} = {x}^{2} + 4x + 4[/tex]
[tex] {(x - 9)}^{2} = {x}^{2} - 18x + 81[/tex]
[tex] {( \frac{1}{2} - 1) }^{2} = \frac{1}{4} - 1 + 1 = \frac{1}{4} [/tex]
[tex](3x - 7)(3x - 7) = {(3x - 7)}^{2} = 9{x}^{2} - 42x + 49[/tex]
[tex] {(x + 2)}^{2} + {(x - 3)}^{2} - (x + 4)(x - 4)[/tex]
[tex] = {x}^{2} + 4x + 4 + {x}^{2} - 6x + 9 - {x}^{2} + 4[/tex]
[tex] = {x}^{2} - 2x + 17[/tex]
