bonjour

A = ( x - 7 )² - 9

A = x² - 14 x + 49 - 9

A = x² - 14 x + 40

A = ( x - 7 - 3 ) ( x - 7 + 3 )

= ( x - 10 ) ( x - 4 )

A = 0

( x - 10 ) ( x - 4 ) = 0

x = 10 ou 4

A = 40

x² - 14 x + 40 = 40

x²- 14 x = 0

x ( x - 7 ) = 0

x = 0 ou 7

A = 4 x² - 100

A = ( 2 x - 10 ) ( 2 x + 10 )

B = ( 5 + x ) ( 1 - 2 x ) + ( 5 + x ) ( 1 - 3 x )

= ( 5 + x ) ( 1 - 2 x + 1 - 3 x )

= ( 5 + x ) ( - 5 x + 2 )

C = ( x - 3 )²

= x²- 6 x + 9

A = 0

( 2 x - 10 ) ( 2 x + 10 ) = 0

x = 5 ou - 5

A = 69

4 x² - 100 = 69

4 x² - 100 - 69 = 0

4 x² - 169 = 0

4 x² = 169

x² = 169/4

x = √169/4 ou - √169/4

x = 13/2 ou - 13 /2

B = 0

( 5 + x ) ( - 5 x + 2 )

x = - 5 ou 2/5

4 x² - 100 = 4 ( x - 3 )²

4 x² - 100 = 4 ( x² - 6 x + 9 )

4 x² - 100 = 4 x² - 24 x + 36

4 x² - 4 x² + 24 x = 36 + 100

24 x = 136

x = 136/24 = 17/3

A est 4 fois plus grand que C pour x = 17/3