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2014-10-31T09:52:25+01:00
Bonjour

Exercice I

a(x) = 4 x² + 28 x +49 + x² - 153
        = 5 x² + 28 x - 104

b(x) = x² - 22 x + 121 - 5 x²
       - 4 x² - 22 x + 121

c(x) = ( 10 x  - x) ( 10 x + x)

d(x) = 11 x( 11 - 5 x)

exercice II

Aire ABCD = 18 x 4 = 72  cm²

Aire a = ( 4x)/2 = 2x

aire b = 72 - 2 x

72 - 2 x = 4 x
- 2 x - 4 x = - 72
- 6 x = - 72
x = 12
x doit valoir 12 cm

Exercice III

7 x² + 60 x - 27 
( 7 x -3)(x +9) = 7 x² + 63 x  - 3 x - 27 = 7 x²  + 60 x - 27
 -27 + x ( 60 +7 x ) = - 27 + 60 x + 7 x²

E(0) 
7 x² +60 x -27 = - 27

E(-9)
567 - 540 -27 = 20

3) E(x) = ( 7 x - 3) ( x +9)

E(x) = 0

soit  7 x -3 = 0 donc  7 x = 3 et x = 3/7
soit x +9 = 0 et x = -9

E(x) =  -27

7 x² + 60 x -27 = - 27
7 x² + 60 x = -27 + 27
7 x² + 60 x = 0
x = 0