a)(1/radical2 -1+1/radical2 +1)(radical8 - radical2)=4
aducem la acelasi numitor in prima paranteza=> radical2 +1/(radical2 +1)(radical2 -1) +radical2 -1/(radical2 - 1)(radical2 +1)
stii formula: (a-b)(a+b)=a^2-b^2 => numitorii devin 2-1 = 1
2radical2(radical8-radical2)=4 <=>2radical16-2radical4=4 <=> 2*4-2*2=4 <=> 8-4=4 (A)
