phân tích đan thức thành nhân tử: x^4-8x^3+26x^2-39x+24
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\(x^3+9x^2+26x+24\)
\(=x^3+3x^2+6x^2+18x+8x+24\)
\(=\left(x^3+3x^2\right)+\left(6x^2+18x\right)+\left(8x+24\right)\)
\(=x^2\left(x+3\right)+6x\left(x+3\right)+8\left(x+3\right)\)
\(=\left(x+3\right)\left(x^2+6x+8\right)\)
\(=\left(x+3\right)\left(x^2+2x+4x+8\right)\)
\(=\left(x+3\right)\left[\left(x^2+2x\right)+\left(4x+8\right)\right]\)
\(=\left(x+3\right)\left[x\left(x+2\right)+4\left(x+2\right)\right]\)
\(=\left(x+3\right)\left(x+2\right)\left(x+4\right)\)
\(15^3+29x^2-8x-12=15x^3+30x^2-x^2-2x-6x-12\)
= \(15x^2.\left(x+2\right)-x.\left(x+2\right)-6.\left(x+2\right)\)= \(\left(x+2\right).\left(15x^2-x-6\right)\)
= \(\left(x+2\right).\left(15x^2-10x+9x-6\right)\)= \(\left(x+2\right).\left(3x-2\right).\left(5x+3\right)\)
\(x^3+9x^2+26x+24=x^3+3x^2+6x^2+18x+8x+24\)\(=x.^2\left(x+3\right)+6x.\left(x+3\right)+8.\left(x+3\right)\)\(=\left(x+3\right).\left(x^2+6x+8\right)\)\(\left(x+3\right).\left(x^2+2x+4x+8\right)=\left(x+2\right).\left(x+3\right).\left(x+4\right)\)
Ta có : 15x3 + 29x2 - 8x - 12
= 15x3 + 30x2 - x2 - 8x - 12
= 15x(x + 2) - (8x + 16) - (x2 - 4)
= 15x(x + 2) - 8(x + 2) - (x - 2)(x + 2)
= (x + 2)(15x - 8 - x + 2)
= (x + 2) (14x - 6)
click zô nha >_<
Ta có : 15x3 + 29x2 - 8x - 12
= 15x3 + 30x2 - x2 - 8x - 12
= 15x(x + 2) - (8x + 16) - (x2 - 4)
= 15x(x + 2) - 8(x + 2) - (x - 2)(x + 2)
= (x + 2)(15x - 8 - x + 2)
= (x + 2) (14x - 6)
a,x^4+2x^3-4x-4
=(x^3+2x^3)-(4x+4)
=x^3(x+2)-4(x+2)
=(x^3-4)(x+2)
\(X^4+2X^3-4X-4\)
\(=\left(X^2\right)^2+2X^3-4X-2^2\)
\(=\left[\left(X^2\right)^2-2^2\right]+\left[2X^3-4X\right]\)
\(=\left(X^2+2\right)\left(X^2-2\right)+2X\left(X^2-2\right)\)
\(=\left(X^2-2\right)\left(X^2+2+2X\right)\)
Katherine Lilly Filbert nói rất đúng câu hỏi nhiều như vậy ai mà trả lời đc hết cơ chứ
\(x^3+9x^2+26x+24=\left(x^2+7x+12\right)\left(x+2\right)=\left(x+3\right)\left(x+4\right)\left(x+2\right)\)
Ta có: \(x^3+9x^2+26x+24\)
\(=\left(x^3+2x^2\right)+\left(7x^2+14x\right)+\left(12x+24\right)\)
\(=x^2\left(x+2\right)+7x\left(x+2\right)+12\left(x+2\right)\)
\(=\left(x+2\right)\left(x^2+7x+12\right)\)
\(=\left(x+2\right)\left[\left(x^2+3x\right)+\left(4x+12\right)\right]\)
\(=\left(x+2\right)\left[x\left(x+3\right)+4\left(x+3\right)\right]\)
\(=\left(x+2\right)\left(x+3\right)\left(x+4\right)\)
Lời giải:
a.
$x^4+10x^3+26x^2+10x+1$
$=(x^4+10x^3+25x^2)+x^2+10x+1$
$=(x^2+5x)^2+2(x^2+5x)+1-x^2$
$=(x^2+5x+1)^2-x^2=(x^2+5x+1-x)(x^2+5x+1+x)$
$=(x^2+4x+1)(x^2+6x+1)$
b.
$x^4+x^3-4x^2+x+1$
$=(x^4-x^2)+(x^3-x^2)+(x-x^2)+(1-x^2)$
$=x^2(x-1)(x+1)+x^2(x-1)-x(x-1)-(x-1)(x+1)$
$=(x-1)[x^2(x+1)+x^2-x-(x+1)]$
$=(x-1)(x^3+2x^2-2x-1)$
$=(x-1)[(x^3-1)+(2x^2-2x)]=(x-1)[(x-1)(x^2+x+1)+2x(x-1)]$
$=(x-1)(x-1)(x^2+x+1+2x)=(x-1)^2(x^2+3x+1)$