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efectuati ex 11 doar b si d

Efectuati Ex 11 Doar B Si D class=

Răspuns :

b)(2+√7)²=4+4√7+7=11+4√7
d)(5+√5)³=125+75√5+75+5√5=200+8√5
Exercitiul 11

b) (2+√7)²
=2²+2×2×√7+(√7)²
=4+4√7+7

d) (5+√5)³
=5³+3×5²×√5+3×5×(√5)²+(√5)³
=125+75√5+75+5√5
=200+80√5

Formule de calcul prescurtat:

(a+b)²=a²+2ab+b²

(a–b)²=a²–2ab+b²

(a–b)(a+b)=a²–b²

(a+b)³=a³+3a²b+3ab²+b³