bonjour
A = (x-1)²-(3-x)(3+x)
= x² - 2 x + 1 - ( 9 - x²)
= x² - 2 x + 1 - 9 + x²
= 2 x² - 2 x - 8
B = 5-(x+7)²
= 5 - ( x² + 14 x + 49 )
= 5 - x² - 14 x - 49
= - x² - 14 x - 44
C = (4x-1)²-(2-5x)(2+5x)
= 16 x² - 8 x + 1 - ( 4 - 25 x²)
= 16x² - 8 x + 1 - 4 + 25 x²
= 41 x² - 8 x - 3
D = (x - 2)²-(2x + 3)²
= x² - 4 x + 4 - ( 4 x² + 12 x + 9 )
= x² - 4 x + 4 - 4 x² - 12 x - 9
= - 3 x² - 16 x - 5
2) Factoriser et réduire les expressions suivantes :
E=x²-3xy + 12x
= x ( x - 3 y + 12 )
F = (3x + 2) (20-5x) +3(20- 5x)
= ( 20 - 5 x ) ( 3 x + 2 + 3 )
= ( 20 - 5 x ) ( 3 x+ 5 )
G = (12-7x)(x+20) — 9(12-7x)
= ( 12 - 7 x ) ( x + 20 - 9 )
= ( 12 - 7 x ) ( x + 11 )
H = 6(2x-10) - (2x - 10) (2x + 1)
= ( 2 x - 10 ) ( 6 - 2 x - 1 )
= ( 2 x - 10 ) ( - 2 x + 5 )
