Répondre :
A) E+F.
(2 √5 +3)+( 2√ 5 -1)
= 4√5+2
B) E-F.
(2 √5 +3)-( 2√ 5 -1)
=4
C) E×F
(2 √5 +3)( 2√ 5 -1)
=2²*(√5)²+6√5-2√5-3
=20+4√5-3
=17+4√5
(2 √5 +3)+( 2√ 5 -1)
= 4√5+2
B) E-F.
(2 √5 +3)-( 2√ 5 -1)
=4
C) E×F
(2 √5 +3)( 2√ 5 -1)
=2²*(√5)²+6√5-2√5-3
=20+4√5-3
=17+4√5