Sagot :
B(x)=9 - 49X² - ( 4X+ 1 )(12 - 28X ) - (3 - 7X)²
B(x)=(3+7x)(3-7x)-4(4x+1)(3-7x)-(3-7x)²
B(x)=(3-7x)(3+7x-4(4x+1)-(3-7x))
B(x)=(3-7x)(3+7x-16x-4-3+7x)
B(x)=(3-7x)(-2x-4)
voila =)
B(x) = 9 - 49X² - ( 4X+ 1 )(12 - 28X ) - (3 - 7X)²
(3-7x)(3+7x)-(4x+1)4(3-7x)-(3-7x)(3-7x)
(3+7x)(3+7x+4-3+7x)
(3+7x)(14x+4)
B(x) = 9 - 49X² - ( 4X+ 1 )(12 - 28X ) - (3 - 7X)²
9 - 49x² -48x-112x²+12-28x-(9-42x+49x²)
-161x²-76x+3-9+42x-49x²=-210x²-34x-6
bonne chance