Sagot :
Réponse :
bonsoir
A = - 9 + 5 ( 5 x² + 1 )
A = - 9 + 25 x² + 5 = 25 x² - 4
25 x² - 4 = ( 5 x - 2 ) ( 5 x + 2 )
si = 2 , a = ( 10 - 2 ) ( 10 + 2 ) = 8*12 = 96
A = - 6x² + 15 x - 3 x² - 3 x
= - 9 x² + 12 x
B = - 2 x² - 2 x + 5 x + 5
= - 2 x² + 3 x + 5
C = 4 x² - 20 x + 25 + x² - 2 x + 1
= 5 x² - 22 x + 26
Explications étape par étape :
Bonsoir,
F.
A = -9 + 5 (5x² + 1)
1) A = -9 + 5 (5x² + 1) = -9 + 5 * 5x² + 5 = 25x² - 9 + 5 = 25x² - 4
2) A = (5x)² - 2² = (5x - 2) (5x + 2)
3) si x = 2 alors A = (10 - 2) ( 10 + 2) = 8 * 12 = 96
si x = -2 alors A = (-10 - 2) (-10 + 2) = -12 * (-8) = 12 * 8 = 96
G.
A = -3x (2x - 5) + 3x (-x - 1)
A = -3x (2x - 5) - 3x (x + 1)
A = -3x (2x - 5 + x + 1)
A = -3x (3x - 4)
A = -9x² + 12x
B= (2x - 5) (-x - 1)
B = -2x² - 2x + 5x + 5
B = -2x² + 3x + 5
C= (2x - 5)² + (x - 1)²
C = 4x² - 20x + 25 + x² - 2x + 1
C = 5x² - 22x + 26