Sagot :
bonjour
d = ( x + 1 ) ( x + 3 - 2 ) = ( x + 1 ) ( x + 1 )
e = ( 2 x - 3 ) ( 2 x - 3 + x + 1 ) = ( 2 x - 3 ) ( 3 x - 2 )
f = ( 2 x + x + 7 ) ( 2 x - x - 7 ) = ( 3 x + 7 ) ( x - 7 )
g = ( x - 1 ) ( x - 1 - 2 x - 10 ) = ( x - 1 ) ( - x - 11 )
allez fias le dernier pour la route et x² - 4 = ( x - 2 ) ( x + 2 )
Bonjour,
D = (x+1)(x+3) - 2(x+1)
= (x+1)[(x+3) - 2)]
= (x+1)(x+1)
= (x+1)²
E = (2x-3)² + (2x-3)(x+1)
= (2x-3)(2x-3) + (2x-3)(x+1)
= (2x-3)[(2x-3)+(x+1)]
= (2x-3)(3x-2)
F = 4x² - (x+7)²
= (2x)² - (x+7)²
= [2x+(x+7)][2x-(x+7)] car a²-b² = (a+b)(a-b)
= (3x+7)(x-7)
G = (x-1)² - 2(x-1)(x+5)
= (x-1)(x-1) - 2(x-1)(x+5)
= (x-1)[(x-1)-2(x+5)]
= (x-1)(x-2x-1-10)
= (x-1)(-x-11)
= -(x-1)(x+11)
H = 3x(x-2) + (x²-4) - 5(x-2)
on sait que x²-4 = (x+2)(x-2) car a²-b² = (a+b)(a-b)
donc : H = 3x(x-2) + (x+2)(x-2) - 5(x-2)
= (x-2)[3x+(x+2)-5]
= (x-2)(4x-3)