А) (√5-1)(√5+1) Б) (√5-1)(√5+2) в) (√5+2)^2 г) (√5+2)(√5+1) - (√5-2)(√5-1)

[latex](a-b)*(a+b) = a^2-b^2\\A\\ ( \sqrt{5} - 1) *( \sqrt{5}+1 ) = 5 - 1 = 4\\B\\( \sqrt{5} - 1) *( \sqrt{5}+2 ) = ( \sqrt{5} - 1) *( (\sqrt{5}+1) + 1 ) = 5 - 1 + \sqrt{5} - 1= \sqrt{5} +3[/latex] [latex]C\\( \sqrt{5}+2 )^2 = 5 + 4 +4* \sqrt{5}  = 9 + 4* \sqrt{5}\\[/latex] [latex]D\\ ( \sqrt{5}+2 )*( \sqrt{5}+1 )-( \sqrt{5}-2 )*( \sqrt{5}-1 ) =(( \sqrt{5}+1) +1)*( \sqrt{5}+1 )-(( \sqrt{5}-1) -1)*( \sqrt{5}-1 ) = ( \sqrt{5}+1 )^2 + ( \sqrt{5}+1 ) - ( \sqrt{5}-1)^2+( \sqrt{5}-1) = 6* \sqrt{5}[/latex]