Réponses

2014-06-02T17:57:23+02:00
BOnsoir

N°9

A = 2√45 - 5√20 - √80
A = 6√5 - 10√5- 4√5
A = -8√5

B = √50 - 3√8 +2√18
B = 5√2 - 6√2 + 6√2
B = 5√2

C = 4√45 + 2√5 - √500
C = 12√5 +2√5 - 10√5
C = 4√5

D = √75 + 4√12
D = 5√3 + 8√3
D = 13√3

E = 2√5 - √20 -3√45
E = 2√5 - 2√5 - 9√5
E = -9√5

N°10

A = 5√18 = 15√2
B = 3√50 = 15√2

C = 2 - √2  et D = 2 + √2
C x D = ( (2 -√2)(2 +√2) identité remarquable
= 4 - 2 = 2

C² = (2 -√2)² = 4 - 4√2 + 2 = 6 - 4√2


N°11
(2 + √3)² + (1 -2√3)²
4 + 4√3 + 3 + ( 1 - 4√3 + 12)
= 4 + 4√3 + 3 + 1 -4√3 +12
= 20

(2 - √3) ( 2 + √3)
= 4 - 3 = 1