Giải pt \(x^4+2012x^2-2013=0\)
K
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L
1
23 tháng 8 2018
\(2012x^2-x-2013=0\)
\(\Rightarrow2012x^2+2012x-2013x-2013=0\)
\(\Rightarrow2012x\left(x+1\right)-2013\left(x+1\right)=0\)
\(\Rightarrow\left(2012x-2013\right)\left(x+1\right)=0\)
\(\Rightarrow\orbr{\begin{cases}2012x-2013=0\\x+1=0\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{2013}{2012}\\x=-1\end{cases}}}\)
Chúc bạn học tốt.
KM
1
25 tháng 8 2020
hải anh giải phương trình 2 nhé
Điều kiện xác định \(x\ge1\)
\(3\left(x^2-x+1\right)=\left(x+\sqrt{x-1}\right)^2\)
\(\Leftrightarrow3\left(x-\sqrt{x-1}\right)\left(x+\sqrt{x-1}\right)=\left(x+\sqrt{x-1}\right)^2\)
\(\Leftrightarrow\left(x+\sqrt{x-1}\right)\left(3x-3\sqrt{x-1}-x-\sqrt{x-1}\right)=0\)
\(\Leftrightarrow2\left(x+\sqrt{x-1}\right)\left(x-2\sqrt{x-1}\right)=0\)(vì x\(\ge\)1 nên \(x+\sqrt{x-1}\ne0\))
\(\Leftrightarrow x-1-2\sqrt{x-1}+1=0\)
\(\Leftrightarrow\left(\sqrt{x-1}-1\right)^2=0\)
\(\Leftrightarrow\sqrt{x-1}=1\)
\(\Leftrightarrow x=2\)(thỏa mãn điều kiện xác định)
Vậy phương trình có nghiệm x=2
NT
7 tháng 4 2017
Ta có:
\(x^4+2013x^2+2012x+2013=x^4+2013x^2+2013x+2013-x\)
\(=\left(x^4-x\right)+\left(2013x^2+2013x+2013\right)\)
\(=x\left(x^3-1\right)+2013\left(x^2+x+1\right)\)
\(=x\left(x-1\right)\left(x^2+x+1\right)+2013\left(x^2+x+1\right)\)
\(=\left(x^2-x+2013\right)\left(x^2+x+1\right)\)
1 tháng 3 2019
b) \(\dfrac{5x-150}{50}+\dfrac{5x-102}{49}+\dfrac{5x-56}{48}+\dfrac{5x-12}{47}+\dfrac{5x-660}{46}=0\)
\(\Leftrightarrow\dfrac{5x-150}{50}-1+\dfrac{5x-102}{49}-2+\dfrac{5x-56}{48}-3+\dfrac{5x-12}{47}-4+\dfrac{5x-660}{46}+10=0\)
\(\Leftrightarrow\dfrac{5x-200}{50}+\dfrac{5x-200}{49}+\dfrac{5x-200}{48}+\dfrac{5x-200}{47}+\dfrac{5x-200}{46}=0\)
\(\Leftrightarrow\left(5x-200\right)\left(\dfrac{1}{50}+\dfrac{1}{49}+\dfrac{1}{48}+\dfrac{1}{47}+\dfrac{1}{46}\right)=0\)
\(\Leftrightarrow5x-200=0\)
\(\Leftrightarrow x=40\)
LA
1 tháng 3 2019
b)
\(\dfrac{5x-150}{50}+\dfrac{5x-102}{49}+\dfrac{5x-56}{48}+\dfrac{5x-12}{47}+\dfrac{5x-660}{46}=0\)
\(\Rightarrow\left(\dfrac{5x-150}{50}-1\right)+\left(\dfrac{5x-102}{49}-2\right)+\left(\dfrac{5x-56}{48}-3\right)+\left(\dfrac{5x-12}{47}-4\right)\)
\(+\left(\dfrac{5x-660}{46}+10\right)=0\)
\(\Rightarrow\dfrac{5x-200}{50}+\dfrac{5x-200}{49}+\dfrac{5x-200}{48}+\dfrac{5x-200}{47}+\dfrac{5x-200}{46}=0\)
\(\Rightarrow\left(5x-200\right)\left(\dfrac{1}{50}+\dfrac{1}{49}+\dfrac{1}{48}+\dfrac{1}{47}+\dfrac{1}{46}\right)=0\)
\(\dfrac{1}{50}+\dfrac{1}{49}+\dfrac{1}{48}+\dfrac{1}{47}+\dfrac{1}{46}\ne0\)
\(\Rightarrow5x-200=0\Rightarrow x=40\)
KN
1
ND
Nguyễn Đức Trí
VIP
18 tháng 8 2023
\(x^2+xy-2012x-2013y-2014=0\)
\(\Leftrightarrow x\left(x+y\right)-2013x-2013y+x-2013-1=0\)
\(\Leftrightarrow x\left(x+y\right)-2013\left(x+y\right)+\left(x-2013\right)-1=0\)
\(\Leftrightarrow\left(x+y\right)\left(x-2013\right)+\left(x-2013\right)-1=0\)
\(\Leftrightarrow\left(x-2013\right)\left(x+y+1\right)=1\)
\(\Leftrightarrow\left(x-2013\right);\left(x+y+1\right)\in\left\{-1;1\right\}\)
\(\Leftrightarrow\left(x;y\right)\in\left\{\left(2012;-2014\right);\left(2014;-2014\right)\right\}\left(x;y\inℤ\right)\)
NH
2
7 tháng 5 2017
\(\dfrac{x-5}{2012}+\dfrac{x-4}{2013}=\dfrac{x-3}{2014}+\dfrac{x-2}{2015}\)
\(\Rightarrow\left(\dfrac{x-5}{2012}-1\right)+\left(\dfrac{x-4}{2013}-1\right)=\left(\dfrac{x-3}{2014}-1\right)+\left(\dfrac{x-2}{2015}-1\right)\)
\(\Leftrightarrow\dfrac{x-2017}{2012}+\dfrac{x-2017}{2013}=\dfrac{x-2017}{2014}+\dfrac{x-2017}{2015}\)
\(\Leftrightarrow\dfrac{x-2017}{2012}+\dfrac{x-2017}{2013}-\dfrac{x-2017}{2014}-\dfrac{x-2017}{2015}=0\)
\(\Leftrightarrow\left(x-2017\right)\left(\dfrac{1}{2012}+\dfrac{1}{2013}-\dfrac{1}{2014}-\dfrac{1}{2015}\right)=0\)
\(\Rightarrow x-2017=0\Leftrightarrow x=2017\)
Vậy x = 2017
QT
2
12 tháng 1 2018
x^4+2013x^2+2012x+2013
=(x^4-x)+(2013x^2+2013x+2013)
=x(x^3-1)+2013(x^2+x+1)
=x(x-1)(x^2+x+1)+2013(x^2+x+1)
=(x^2+x+1)(x^2-x+2013)
chúc bạn học tốt ^ ^
HL
12 tháng 1 2018
\(x^4+2013x^2+2012x+2013\)
=\(x^4+2013x^2+2013x-x+2013\)
=\(\left(x^4-x\right)+\left(2013x^2+2013x+2013\right)\)
=\(x\left(x^3-1\right)+2013\left(x^2+x+1\right)\)
=\(x\left(x-1\right)\left(x^2+x+1\right)+2013\left(x^2+x+1\right)\)
=\(\left(x^2+x+1\right)\left(x^2-x+2013\right)\)
Ta có : \(x^4+2012x^2-2013=0\)
=> \(x^4-x^2+2013x^2-2013=0\)
=> \(x^2\left(x^2-1\right)+2013\left(x^2-1\right)=0\)
=> \(\left(x^2+2013\right)\left(x^2-1\right)=0\)
=> \(\left(x^2+2013\right)\left(x-1\right)\left(x+1\right)=0\)
Mà \(x^2+2013>0\)
=> \(x^2-1=0\)
=> \(x=\pm1\)
Vậy phương trình có nghiệm là \(S=\left\{1,-1\right\}\)
Lời giải:
$x^4+2012x^2-2013=0$
$\Leftrightarrow x^4-x^2+2013x^2-2013=0$
$\Leftrightarrow x^2(x^2-1)+2013(x^2-1)=0$
$\Leftrightarrow (x^2-1)(x^2+2013)=0$
Dễ thấy $x^2+2013\geq 2013>0$ với mọi $x\in\mathbb{R}$ nên $x^2-1=0$
$\Rightarrow x=\pm 1$