(√ 5 + 1) (√ 5-1) = (2 - √ 7) (√ 7 + 2) = (2 √ 3 + 1) square (7 - √ 3) (2 √ 3 + 1)= (√ 5 + 1) (√ 5-1) = (2 - √ 7) (√ 7 + 2) = (2 √ 3 + 1) square =? (7-√3)(2√3+1)=

(√ 5 + 1) (√ 5-1) = (2 - √ 7) (√ 7 + 2) = (2 √ 3 + 1) square (7 - √ 3) (2 √ 3 + 1)= (√ 5 + 1) (√ 5-1) = (2 - √ 7) (√ 7 + 2) = (2 √ 3 + 1) square =? (7-√3)(2√3+1)=

(√5+1)(√5-1)= (√5)²-1²=4;
(2-√ 7)(√7+2)=2²-(√7)²=-3;
(2 √ 3 + 1) square = (2 √ 3) & sup2; + 2 × 2 √ 3 × 1 + 1 = 13 + 4 √ 3;
(7-√3)(2√3+1)= 14√3+7-6-√3=13√3+1