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\(x^3-4x^2-8x+8\)
\(\Leftrightarrow\left(x^3-4x^2\right)-\left(8x-8\right)\)
\(\Leftrightarrow x^2\left(x-4\right)-4\left(x-4\right)\)
\(\Leftrightarrow\left(x-4\right)\left(x^2-4\right)\)
\(1.6x\left(x-10\right)-2x+20=0\)
⇔\(6x\left(x-10\right)-2\left(x-10\right)=0\)
⇔ \(2\left(x-10\right)\left(3x-1\right)=0\)
⇔ x = 10 hoặc x = \(\dfrac{1}{3}\)
KL....
\(2.3x^2\left(x-3\right)+3\left(3-x\right)=0\)
⇔ \(3\left(x-3\right)\left(x^2-1\right)=0\)
⇔ \(x=+-1\) hoặc \(x=3\)
KL....
\(3.x^2-8x+16=2\left(x-4\right)\)
⇔ \(\left(x-4\right)^2-2\left(x-4\right)=0\)
⇔ \(\left(x-4\right)\left(x-6\right)=0\)
⇔ \(x=4\) hoặc \(x=6\)
KL.....
\(4.x^2-16+7x\left(x+4\right)=0\)
\(\text{⇔}4\left(x+4\right)\left(2x-1\right)=0\)
⇔ \(x=-4hoacx=\dfrac{1}{2}\)
KL.....
\(5.x^2-13x-14=0\)
⇔ \(x^2+x-14x-14=0\)
\(\text{⇔}\left(x+1\right)\left(x-14\right)=0\)
\(\text{⇔}x=14hoacx=-1\)
KL......
Còn lại tương tự ( dài quá ~ )
\(x^4+1\)
\(=x^4+2x^2+1-2x^2\)
\(=\left(x^2+1\right)^2-2x^2\)
\(=\left(x^2+1\right)^2-\left(\sqrt{2}x\right)^2\)
\(=\left(x^2+1-\sqrt{2}x\right)\left(x^2+1+\sqrt{2}x\right)\)
Lời giải:
a) ĐKXĐ: $x\neq \pm 1$
\(\frac{x^4-4x^2+3}{x^4+6x^2-7}=\frac{x^2(x^2-1)-3(x^2-1)}{x^2(x^2-1)+7(x^2-1)}=\frac{(x^2-3)(x^2-1)}{(x^2-1)(x^2+7)}=\frac{x^2-3}{x^2+7}\)
b) ĐKXĐ: Với mọi $x\in\mathbb{R}$
\(\frac{x^4+x^3-x-1}{x^4+x^4+2x^2+x+1}=\frac{(x^4-x)+(x^3-1)}{(x^4+x^3+x^2)+(x^2+x+1)}=\frac{x(x^3-1)+(x^3-1)}{x^2(x^2+x+1)+(x^2+x+1)}\)
\(=\frac{(x^3-1)(x+1)}{(x^2+1)(x^2+x+1)}=\frac{(x-1)(x^2+x+1)(x+1)}{(x^2+1)(x^2+x+1)}=\frac{x^2-1}{x^2+1}\)
c) ĐK: $x\neq 1;-2$
\(\frac{x^3+3x^2-4}{x^3-3x+2}=\frac{x^2(x-1)+4(x^2-1)}{x^2(x-1)+x(x-1)-2(x-1)}=\frac{(x-1)(x^2+4x+4)}{(x-1)(x^2+x-2)}\)
\(=\frac{(x-1)(x+2)^2}{(x-1)(x-1)(x+2)}=\frac{x+2}{x-1}\)
d) ĐK: $x^2+3x-1\neq 0$
\(\frac{x^4+6x^3+9x^2-1}{x^4+6x^3+7x^2-6x+1}=\frac{(x^2+3x)^2-1}{(x^2+3x)^2-2x^2-6x+1}\)
\(=\frac{(x^2+3x-1)(x^2+3x+1)}{(x^2+3x)^2-2(x^2+3x)+1}=\frac{(x^2+3x-1)(x^2+3x+1)}{(x^2+3x-1)^2}=\frac{x^2+3x+1}{x^2+3x-1}\)
a) Gần giống cho nó giống luôn.
cần thêm (-x^3+2x^2-x) là giống
\(\left(x-1\right)^4+x^3-2x^2+x=\left(x-1\right)^4+x\left(x^2-2x+1\right)=\left(x-1\right)^4+x\left(x-1\right)^2\)
\(\left(x-1\right)^2\left[\left(x-1\right)^2+x\right]\)
\(\left[\begin{matrix}x-1=0\Rightarrow x=0\\\left(x-1\right)^2+x=\left(x-\frac{1}{2}\right)^2+\frac{3}{4}=0\end{matrix}\right.\)
Nghiệm duy nhất: x=1
a)( 6x - 2)2 ( 5x - 2)2 - 2( 6x - 2 )( 5x - 2 )
=(6x-2)2-2(6x-2)(5x-2)+(5x-2)2
=[(6x-2)-(5x-2)]2
=(6x-2-5x+2)2
=X2
b) ( x2 + 3x + 1)2 - 2( x2 + 3x + 1)( 3x + 1) + ( 9x2 - 6x + 1)
=( x2 + 3x + 1)2 - 2( x2 + 3x + 1)( 3x + 1)+[(3x)2-2.3x.1+12]
=( x2 + 3x + 1)2 - 2( x2 + 3x + 1)( 3x + 1)+(3x+1)2
=[( x2 + 3x + 1)-( 3x + 1)]2
=( x2 + 3x + 1- 3x - 1)2
=(x2)2
=x4
a) x3 + 2x - 3
=x3+x2+3x-x2+x+3
=x(x2+x+3)-1(x2+x+3)
=(x-1)(x2+x+3)
b) x3 - x2 + x + 3
=x3-2x2+3x+x2-2x+3
=x(x2-2x+3)+1(x2-2x+3)
=(x+1)(x2-2x+3)
c) 3x3 - 4x2 + 13x - 4
=3x3-3x2+12-x2-x+4
=3x(x2-x+4)-1(x2-x+4)
=(3x-1)(x2-x+4)
d) 6x3 + x2 + x + 1
=6x3-2x2+2x+3x2-x+1
=2x(3x2-x+1)+1(3x2-x+1)
=(2x+1)(3x2-x+1)
e)bạn phân tích tương tự nhé mk cho đáp án để bạn đổi chiếu nè
=(2x+1)(2x2+2x+1)
\(a)\)
\(\left(x^2+4x\right)^2+9x^2-6x\left(x^2+4x\right)\)
\(=\left(x^2+4x\right)\left(x^2+4x-6x\right)+9x^2\)
\(=\left(x^2+4x\right)\left(x^2-2x\right)+9x^2\)
\(=x\left(x+4\right)x\left(x-2\right)+9x^2\)
\(=x^2\left(x^2+4x-2x-8\right)+9x^2\)
\(=x^2\left(x^2+2x-8\right)+9x^2\)
\(=x^4+2x^3-8x^2+9x^2\)
\(=x^4+2x^3+x^2\)
\(=x^2\left(x^2+2x+1\right)\)
\(=x^2\left(x+1\right)^2\)
\(b)\)
\(\left(-6x^3+7x^2-4x+1\right):\left(-2+1\right)\)
\(=\left(-6x^3+7x^2-4x+1\right)\left(-1\right)\)
\(=6x^3-7x^2+4x-1\)
\(c)\)
\(\left(x-1\right)\left(x-2\right)\left(3x-4\right)\)
\(=\left(x^2-3x+2\right)\left(3x-4\right)\)
\(=3x^3-4x^2-9x^2+12x+6x-8\)
\(=3x^3-13x^2+18x-8\)
a) 4x3 - 13x2 + 9x - 18
= 4x3 - 12x2 - x2 + 3x + 6x - 18
= 4x2( x - 3) - x( x - 3) + 6( x - 3)
= ( x - 3)( 4x2 - x + 6)
b) - x3 - 6x2 + 6x + 1
= 6x( 1 - x) + 1 - x3
= 6x( 1 - x) + ( 1 - x )( x2 + x + 1)
= ( 1 - x)( x2 + 7x + 1)
c) x3 + 3x2 + 3x + 2
= x3 + 2x2 + x2 + 2x + x + 2
= x2( x + 2) + x( x + 2) + x + 2
= ( x + 2)( x2 + x + 1)
a) \(4x^3-13x^2+9x-18\)
\(=4x^3-12x^2-x^2+3x+6x-18\)
\(=4x^2\left(x-3\right)-x\left(x-3\right)+6\left(x-3\right)\)
\(=\left(x-3\right)\left(4x^2-x+6\right)\)