[tex]a)\\\\(x-5)(x+5)=x^2-5^2=x^2-25\\\\b)\\\\(10+x)(10-x)=10^2-x^2=100-x^2\\\\c)\\\\(a-\frac{1}{4}b)(a+\frac{1}{4}b)=a^2-(\frac{1}{4}b)^2=a^2-\frac{1}{16}b^2[/tex]
[tex]d)\\\\ (\frac{2}{3}a+b)(\frac{2}{3}a-b)=(\frac{2}{3}a)^2-b^2=\frac{4}{9}a^2-b^2\\\\e)\\\\(0,3s-2t)(2t+0,3s)=(0,3s-2t)( 0,3s+2t)=(0,3s)^2-(2t)^2=0,09s^2-4t^2\\\\f)\\\\(0,5s+0,6t)(0,6t-0,5s)=( 0,6t+0,5s)(0,6t-0,5s)=(0,6t)^2-(0,5s)^2=\\\\=0,36t^2-0,25s^2[/tex]
[tex]stosujemy\ wzor:\\\\(a-b)(a+b)=a^2-b^2[/tex]
