bonjour
f (x) = ( x + 2 ) ( 3 - 5 x ) - ( x + 2 ) ( 4 - 6 x )
f (x) = 3 x - 5 x² + 6 - 10 x - ( 4 x - 6 x² + 8 - 12 x )
f (x) = ( x + 2 ) ( 3 - 5 x - 4 + 6 x )
f (x) = ( x + 2 ) ( x - 1 )
f (x) = - 5 x² - 7 x + 6 - 4 x + 6 x² - 8 + 12 x
f (x) = x² + x - 2
f (x) = ( x + 1/2 )² - 9 /4
f (x) = x² + 2 x /2 + 1/4 - 9 /4 = x² + x - 2
f ( 0 ) = ( 0 + 2 ) ( 0 - 1 ) = 2 * - 1 = - 2
f ( - 1/2 ) = ( - 1/2 + 2 ) ( - 1 /2 - 1 ) = 1.5 * - 2.5 = - 3.75
f ( 1 ) = 3 * 0 = 0
f (x ) = 0
( x + 2 ) ( x - 1 ) = 0
x = - 2 ou 1
f (x ) - 9 /4
( x + 1/2)² - 9/4 = - 9 /4
( x + 1 /2)² = 0
x = - 1/2
f (x) = - 2
x² + x - 2 = - 2
x² + x = 0
x ( x + 1 ) = 0
x = 0 ou - 1
