Odpowiedź:
Korzystamy ze wzoru
[tex](a-b)(a+b)=a^{2} -b^{2}[/tex]
[tex]a) (a-\frac{1}{4} )(a +\frac{1}{4} )=a^{2} -(\frac{1}{4} )^{2} =a^{2} -\frac{1}{16} \\[/tex]
[tex]b) (x+2y)(x-2y)=x^{2} -4y^{2}[/tex]
[tex]c)(2a-5)(2a+5)=(2a)^{2} -5^{2}=4a^{2} -25[/tex]
[tex]d)(6a-2b)(6a+2b)=36a^{2} -4b^{2}[/tex]
[tex]e)(4-3x)(4+3x)=16-9x^{2}[/tex]
[tex]f)(1-x^{2} )(1+x^{2} )=1-x^{4}[/tex]
