[tex](2+ \sqrt{3}) ^{4}= ((2+ \sqrt{3}) ^{2} )^{2} = (7+4 \sqrt{3}) ^{2} =97+56 \sqrt{3} [/tex]
[tex](2- \sqrt{3}) ^{4}=(( 2- \sqrt{3}) ^{2} )^{2}= (1-4 \sqrt{3}) ^{2}=49-8 \sqrt{3} [/tex]
Expresia devine:
[tex]97+56 \sqrt{3}+49-8 \sqrt{3} =146+48 \sqrt{3} [/tex]