x³-3x²+4=0

⇔x³+x²-4x²-4x+4x+4=0

⇔(x³+x²⁾-(4x²+4x)+(4x+4)=0

⇔x²(x+1)-4x(x+1)+4(x+1)=0

⇔(x+1)(x²-4x+4)=0

⇔(x+1)(x-2)²=0

=>\(\left\{{}\begin{matrix}x+1=0\\x-2=0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-1\\x=2\end{matrix}\right.\)

vậy S={-1;2}

(x³+x²)-(4x²-4x)+(4x+4)=0

=> x²(x+1)-4x(x+1)+4(x+1)=0

=> (x²-4x+4)(x+1)=0

=> (x-2)²(x+1)=0

=> \(\left[{}\begin{matrix}x-2=0\\x+1=0\end{matrix}\right.\)

=> \(\left[{}\begin{matrix}x=2\\x=-1\end{matrix}\right.\)

\(x^3+4x^2+x+6=0\)

\(\Leftrightarrow\text{ (x + 3).(x + 2).(x - 1) = 0 }\)

<=>

Tự làm nhé mk nhẩm ko nhầm là dậy :D

\(x^3+4x^2+x-6=x^3-x^2+5x^2-5x+6x-6=x^2\left(x-1\right)+5x\left(x-1\right)+6\left(x-1\right)=\left(x-1\right)\left(x^2+5x+6\right)=\left(x-1\right)\left(x^2+2x+3x+6\right)=\left(x-1\right)\left(x+2\right)\left(x+3\right)\)

chúc bạn học tốt

\(x^3-6x^2-x+6=0\)

\(\Leftrightarrow x^2\left(x-6\right)-\left(x-6\right)=0\)

\(\Leftrightarrow\left(x-6\right)\left(x^2-1\right)=0\)

\(\Leftrightarrow\left(x-6\right)\left(x-1\right)\left(x+1\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x-6=0\\x-1=0\\x+1=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=1\\x=-1\end{matrix}\right.\)

Vậy ................................

Bài nào bn

Dat x²+2x+2=a (a>0)

pt<=> \(\dfrac{a-1}{a}+\dfrac{a}{a+1}=\dfrac{7}{6}\)

=> \(\dfrac{\left(a-1\right)\left(a+1\right)}{a\left(a+1\right)}+\dfrac{a.a}{a\left(a+1\right)}=\dfrac{7}{6}\)

=> \(\dfrac{a^2-1}{a\left(a+1\right)}+\dfrac{a^2}{a\left(a+1\right)}=\dfrac{7}{6}\)

=> (2a²-1).6=7a(a+1)

=> 12a²-6=7a²+7a

=> 5a²-7a-6=0

\(\dfrac{x^2+2x+1}{x^2+2x+2}+\dfrac{x^2+2x+2}{x^2+2x+3}=\dfrac{7}{6}\)

Đặt x² + 2x + 1 = t, ta có:

\(\dfrac{t}{t+1}+\dfrac{t+1}{t+2}=\dfrac{7}{6}\)

\(\Leftrightarrow\)\(\dfrac{t\left(t+2\right)}{\left(t+1\right)\left(t+2\right)}+\dfrac{\left(t+1\right)^2}{\left(t+2\right)\left(t+1\right)}=\dfrac{7}{6}\)

\(\Leftrightarrow\) \(\dfrac{t^2+2t}{t^2+3t+2}+\dfrac{t^2+2t+1}{t^2+3t+2}=\dfrac{7}{6}\)

\(\Leftrightarrow\)\(\dfrac{t^2+2t+t^2+2t+1}{t^2+3t+2}=\dfrac{7}{6}\)

\(\Leftrightarrow\)\(\dfrac{2t^2+4t+1}{t^2+3t+2}=\dfrac{7}{6}\)

\(\Leftrightarrow\)6(2t²+4t+1) = 7(t² + 3t + 2)

\(\Leftrightarrow\) 12t² + 24t + 6 = 7t² + 21t + 14

\(\Leftrightarrow\) 12t² + 24t + 6 - 7t² - 21t - 14 = 0

\(\Leftrightarrow\) 5t² + 3t - 8 = 0

\(\Leftrightarrow\) 5t² - 5t + 8t - 8 = 0

\(\Leftrightarrow\) 5t(t - 1) + 8(t - 1) = 0

\(\Leftrightarrow\) (5t + 8)(t - 1) = 0

\(\Leftrightarrow\)\(\left\{{}\begin{matrix}5t+8=0\\t-1=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}t=-\dfrac{8}{5}\\t=1\end{matrix}\right.\)

\(\Leftrightarrow\)\(\left\{{}\begin{matrix}x^2+2x+1=-\dfrac{8}{5}\left(vôlívì:x^2+2x+1=\left(x+1\right)^2\ge0>-\dfrac{8}{5}\right)\\x^2+2x+1=1\end{matrix}\right.\)\(\Leftrightarrow\)x² + 2x + 1 = 1

\(\Leftrightarrow\) x² + 2x = 0

\(\Leftrightarrow\)x(x + 2) = 0

\(\Leftrightarrow\) \(\left\{{}\begin{matrix}x=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=0\\x=-2\end{matrix}\right.\)

Vậy phương trình có n₀ là S={-2;0}

Nhận thấy \(x=0\) không phải nghiệm, chia 2 vế cho \(x^2\)

\(6x^2+7x-36+\frac{7}{x}+\frac{6}{x^2}=0\)

\(\Leftrightarrow6\left(x^2+\frac{1}{x^2}\right)+7\left(x+\frac{1}{x}\right)-36=0\)

Đặt \(x+\frac{1}{x}=a\) (\(\left|a\right|\ge2\)) \(\Rightarrow x^2+\frac{1}{x^2}=a^2-2\)

\(6\left(a^2-2\right)+7a-36=0\)

\(\Leftrightarrow6a^2+7a-48=0\)

Nghiệm xấu

Tôi nghĩ là như này :)) Sai thì chịu nhá :((

Ta có pt : \(\left|x+1\right|+3\left|x-1\right|=x+2+\left|x\right|+2\left|x-2\right|\) (1)

Ta thấy VT pt (1) là : \(\left|x+1\right|+3\left|x-1\right|\ge0\forall x\)

Nên VP pt (1) cũng phải lớn hơn bằng 0

Có nghĩa là \(x+2\ge0\) \(\Leftrightarrow x\ge-2\)

Khi đó : \(\left\{{}\begin{matrix}\left|x+1\right|=-\left(x+1\right)\\3\left|x-1\right|=3\left(1-x\right)\\\left|x\right|=-x\\2\left|x-2\right|=2\left(2-x\right)\end{matrix}\right.\)

Vậy pt (1) \(\Leftrightarrow-x-1+3-3x=x+2-x+4-2x\)

\(\Leftrightarrow2x=-4\Leftrightarrow x=-2\) ( thỏa mãn )

Vậy \(x=-2\) thỏa mãn pt.

-1 0 1 2

1) x=-2/3>-1( loại)

2)

Các thị thức trong dấu giá trị tuyệt đối có nghiệm là: \(\pm1;0;2\)

\(\Rightarrow\) Ta xét pt trong các khoảng sau:

\(\left\{{}\begin{matrix}x< -1\\-1\le x< 0\\0\le x< 1\\1\le x< 2\end{matrix}\right.\)

Với: \(x< -1\) thì:

\(\left\{{}\begin{matrix}\left|x+1\right|=-\left(x+1\right)\\\left|x-1\right|=-\left(x-1\right)\\\left|x\right|=-x\\\left|x-2\right|=-\left(x-2\right)\end{matrix}\right.\)

Và ta có pt sau: \(-\left(x+1\right)-3\left(x-1\right)=x+2-x-2\left(x-20\right)\)

\(\Leftrightarrow x=-2\)

Với \(-1\le x< 0\) ta có pt:

\(\left(x+1\right)-3\left(x-1\right)=x+2-x-2\left(x-20\right)\)

\(\Leftrightarrow0x=8\left(vn\right)\)

Vậy \(\left\{{}\begin{matrix}x=-2\\x\ge2\end{matrix}\right.\)