bonjour
A (x) = 4 x² - 100
A (x) = ( 2 x - 10 ) ( 2 x + 10 )
B (x) = ( 5 + x ) ( 1 - 2 x ) + ( 5 + x ) ( 1 - 3 x )
B (x) = ( 5 + x ) ( 1 - 2 x + 1 - 3 x )
B ( x) = ( 5 + x ) ( - 5 x + 2 )
C(x) = ( x - 3 )²
C (x) = x² - 6 x + 9
A (x) = 0
( 2 x - 10 ) ( 2 x + 10 ) = 0 donc x = 5 ou - 5
A (x) = 69
4 x² - 100 = 69
4 x² = 169
x² = 169/4
x = √169/4 ou - √ 169/4
B = 0
( 5 + x ) ( - 5 x + 2 ) donc 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
