Odpowiedź :
(x - 2)(x + 2) = x² - 2² = x² - 4
(x - 9)(x + 9) = x² - 9² = x² - 81
(2x - 1)(2x + 1) = (2x)² - 1² = 4x² - 1
(6 + 4x)(4x - 6) = (4x)² - 6² = 16x² - 36
a) [tex](x-2)(x+2)=\\=x^2+\not2x-\not2x-4=\\=\boxed{x^2-4}[/tex]
b) [tex](x-9)(x+9)=\\=x^2+\not9x-\not9x-81=\\=\boxed{x^2-81}[/tex]
c) [tex](2x-1)(2x+1)=\\=4x^2+\not2x-\not2x-1=\\=\boxed{4x^2-1}[/tex]
d) [tex](6+4x)(4x-6)=\\=\not24x-36+16x^2-\not24x=\\=\boxed{16x^2-36}[/tex]