Phân tích đa thức sau thành nhân tử ( Phối hợp nhiều phương pháp )

H

harrypham

a, [TEX] -36a^2 - 12ax - x^2=-(36a^2+12ax+x^2)=-[(6a)^2+2 \cdot 6a \cdot x+x^2]=-(6a+x)^2[/TEX].

b, [TEX]x^3 - 8 +6x^2 -12x[/TEX]
[TEX]=(x^3-8)+6x(x-2) [/TEX]
[TEX]=(x-2)(x^2+2x+4)+6x(x-2)[/TEX]
[TEX]=(x-2)(x^2+8x+4)[/TEX]
 
N

ntpt_224

a, -36a^2 - 12ax - x^2 = - (36a^2 + 12ax + x^2) = - (6a+ x) ^2
b, x^3 - 8 + 6x^2 - 12x = x^3 - 2^3 + 6x (x- 2) = (x - 2)( x^2 + 2x + 4) + 6x( x - 2)
= (x - 2)(x^2 +2x + 4 + 6x) = (x- 2)( x^2 + 8x + 4)
 
P

pe_nhock_sock_1999

***
a) -36a^2 - 12ax - x^2=-((6a)^2 + 12ax + x^2)
= -(6a + x)^2
b) x^3 -8 + 6x^2 -12x=6x(x - 2) + x^3 - 2^3
=6x(x - 2) + (x - 2)(x^2 +2x +4)
=(x - 2)(x^2 + 2x + 4 + 6x)
=(x - 2)(x^2 +8x + 4)
*** NHỚ THANKS MÌNH NHA!!! :) :) :)
 
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