👤

Urgent!va rog ! puncte+coroana
1 supra radical din 7 - 2 minus 1 supra radical din 7 + 2


Răspuns :

[1/(√7-2)]-[1/(√7+2)]     rationalizam numitorii
=[(√7+2)/(√7-2)(√7+2)]-[(√7-2)/(√7+2)(√7-2)=
[(√7+2)/(7-4)]-[(√7-2)/(7-4)]=
[(√7+2)/3]-[(√7-2)/3]=
[(√7+2)-(√7-2)]/3=
(√7+2-√7+2)/3=4/3