Răspuns:
[tex](\frac{1}{2x} +3)(\frac{1}{2x}-3)=(\frac{1}{2x} )^{2} -3^{2} =\frac{1}{4x^{2} }-9=\frac{1-9x^{2} }{4x^{2} }[/tex]
[tex](\frac{2}{5a}-1)(\frac{2}{5a}+1)=(\frac{2}{5a} )^{2} -1^{2} =\frac{4}{25a^{2} }-1=\frac{4-25a^{2} }{25a^{2} }[/tex]
[tex](0,2x-4)(0,2x+4)=(0,2x)^{2} -4^{2} =0,04x^{2} -16[/tex]
Explicație pas cu pas:
