2x ( x x 4 ) +5 = 65
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KB
16 tháng 2 2019
ĐKXĐ : \(\forall x\)
Ta có : \(\dfrac{x^2}{x^2+2x+2}+\dfrac{x^2}{x^2-2x+2}-\dfrac{4\left(x^2-5\right)}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow\dfrac{x^2\left(x^2-2x+2\right)+x^2\left(x^2+2x+2\right)-4\left(x^2-5\right)}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow\dfrac{x^4-2x^3+2x^2+x^4+2x^3+2x^2-4x^2+20}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow\dfrac{2x^4+20}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow65\left(2x^4+20\right)=322\left(x^4+4\right)\)
\(\Leftrightarrow130x^4+1300=322x^4+1288\)
\(\Leftrightarrow192x^4-12=0\)
\(\Leftrightarrow x^4=\dfrac{12}{192}\)
\(\Leftrightarrow x^4=\dfrac{1}{16}\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{2}\end{matrix}\right.\)
Vậy ...
NV
Nguyễn Việt Lâm
Giáo viên
16 tháng 2 2019
\(\dfrac{x^2}{x^2+2x+2}+\dfrac{x^2}{x^2-2x+2}-\dfrac{4\left(x^2-5\right)}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow x^2\left(\dfrac{1}{x^2+2+2x}+\dfrac{1}{x^2+2-2x}\right)-\dfrac{4\left(x^2-5\right)}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow x^2\left(\dfrac{2x^2+4}{x^4+4}\right)-\dfrac{4\left(x^2-5\right)}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow\dfrac{2x^4+4x^2-4x^2+20}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow\dfrac{2x^4+20}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow65x^4+650=161x^4+644\)
\(\Leftrightarrow96x^4=6\)
\(\Leftrightarrow x^4=\dfrac{1}{16}\)
\(\Rightarrow x=\pm\dfrac{1}{2}\)
HP
25 tháng 10 2020
b, ĐKXĐ: \(x\ge\frac{5}{2}\)
\(pt\Leftrightarrow\sqrt{2x+4-6\sqrt{2x-5}}+\sqrt{2x-4+2\sqrt{2x-5}}=4\)
\(\Leftrightarrow\sqrt{\left(\sqrt{2x-5}-3\right)^2}+\sqrt{\left(\sqrt{2x-5}+1\right)^2}=4\)
\(\Leftrightarrow\sqrt{2x-5}=3\)
\(\Leftrightarrow x=7\left(tm\right)\)
HP
25 tháng 10 2020
a, ĐKXĐ: \(x\ge5\)
\(pt\Leftrightarrow\sqrt{x-5+4\sqrt{x-5}+4}+\sqrt{x-5+8\sqrt{x-5}+16}=0\)
\(\Leftrightarrow\sqrt{\left(\sqrt{x-5}+2\right)^2}+\sqrt{\left(\sqrt{x-5}+4\right)^2}=0\)
\(\Leftrightarrow2\sqrt{x-5}+6=0\)
\(\Leftrightarrow\sqrt{x-5}=-3\)
Phương trình vô nghiệm
TA
18 tháng 12 2020
a) \(5x-65=5.3^2 \\ 5x-65=45\\5x=45+65\\5x=110\\x=22\)
b) \(200-(2x+6)=4^3\\2x+6=200-4^3\\2x+6=136\\2x=130\\x=65\)
c) \(2(x-51)=2.2^3+20\\2(x-51)=16+20\\2(x-51)=36\\x-51=18\\x=51+18=69\)
d) \(135-5(x+4)=35\\5(x+4)=135-45\\5(x-4)=90\\x-4=18\\x=18+4=22\)
e) \((2x-4)(15-3x)=0\\2(x-2).3(5-x)=0\\(x-2)(5-x)=0\\ \left[ \begin{array}{l}x-2=0\\5-x=0\end{array} \right. \\ \left[ \begin{array}{l}x=2\\x=5\end{array} \right.\)
f) \(2^{x+1} . 2^{2014}=2^{2016} \\ (2^{x+1} . 2^{2014}):2^{2014}=2^{2016} :2^{2014} \\ 2^{x=1}=2^{2016-2014} \\2^{x+1}=2^2\\x+1=2\\x=1\)
g) \(15+(x-1)^3=43\\(x-1)^3=15-42\\(x-1)^3=-27\\(x-1)^3=(-3)^3\\x-1=-3\\x=-2\)
h) \(15-x=17+(-9)\\15-x=17-9\\15-x=8\\x=15-8\\x=7\)
i) \(|x-5|=|-7|+|-4|\\|x-5|=7+4\\|x-5|=11\\ \left[ \begin{array}{l}x-5=11\\x-5=-11\end{array} \right. \\ \left[ \begin{array}{l}x=16\\x=-6\end{array} \right.\)
k) \(|x-3|-12=-9+|-7|\\|x-3|-12=-9+7\\|x-3|-12=-2\\|x-3|=10 \\ \left[ \begin{array}{l}x-3=10\\x-3=-10\end{array} \right. \\ \left[ \begin{array}{l}x=13\\x=-7\end{array} \right.\)
KT
14 tháng 2 2018
\(ĐKXĐ:\) \(\forall x\in Z\)
\(\frac{x^2}{x^2+2x+2}+\frac{x^2}{x^2-2x+2}-\frac{4\left(x^2-5\right)}{x^4+4}=\frac{322}{65}\)
\(\Leftrightarrow\)\(\frac{x^2\left(x^2-2x+2\right)}{\left(x^2+2x+2\right)\left(x^2-2x+2\right)}+\frac{x^2\left(x^2+2x+2\right)}{\left(x^2-2x+2\right)\left(x^2+2x+2\right)}-\frac{4\left(x^2-5\right)}{\left(x^2-2x+2\right)\left(x^2+2x+2\right)}=\frac{322}{65}\)
\(\Leftrightarrow\)\(\frac{x^4-2x^3+2x^2+x^4+2x^3+2x^2-4x^2+20}{\left(x^2-2x+2\right)\left(x^2+2x+2\right)}=\frac{322}{65}\)
\(\Leftrightarrow\)\(\frac{2x^4+10}{x^4+4}=\frac{322}{65}\)
\(\Rightarrow\)\(65\left(2x^4+10\right)=322\left(x^4+4\right)\)
\(\Leftrightarrow\)\(130x^4+650=322x^4+1288\)
\(\Leftrightarrow\)\(192x^4=-638\) (vô lý)
Vậy pt vô nghiệm
P/S:mk lm bừa thôi, đúng thì you tham khảo, sai thì báo mk biết nha
19 tháng 6 2022
\(\Leftrightarrow\dfrac{x^4-2x^3+2x^2+x^4+2x^3+2x^2-4x^2+20}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow\dfrac{2x^4+20}{x^4+4}=\dfrac{322}{65}\)
\(\Leftrightarrow130x^4+1300=322x^4+1288\)
\(\Leftrightarrow-192x^4=-12\)
\(\Leftrightarrow x^4=\dfrac{1}{16}\)
=>x=1/2 hoặc x=-1/2
C
17 tháng 10 2018
65 - 4(2x-30)=5
-4(2x-30)=5-65
-4(2x-30)=-60
2x-30=15
2x=15+30
2x=45
x=45/2
17 tháng 10 2018
65 - 4(2x - 30) = 5
=> 4(2x - 30) = 65 - 5
=> 8x - 120 = 60
=> 8x = 60 + 120
=> 8x = 180
=> x = 9/4
1 tháng 8 2018
a) \(\left(x+1\right)^3+\left(x-2\right)^3-2x^2\left(x-1,5\right)=5\)
\(\Leftrightarrow\left(x^3+3x^2+3x+1\right)+\left(x^3-6x^2+12x-8\right)-\left(2x^3-3x^2\right)=5\)
\(\Leftrightarrow x^3+3x^2+3x+1+x^3-6x^2+12x-8-2x^3+3x^2=5\)
\(\Leftrightarrow15x-12=0\)
\(\Leftrightarrow15x=12\)
\(\Leftrightarrow x=\dfrac{4}{5}\)
Vậy \(S=\left\{\dfrac{4}{5}\right\}\)
(bạn ơi xem lại đề câu b ik để mik giải lun)
MP
15 tháng 10 2018
\(1,\left(\left(3\cdot\left(3x+2\right)\right)+4\cdot\left(x+2\right)\right)-90=0.\)
\(13x-76=0\)
\(13x=76\)
\(x=\frac{76}{13}\)
\(2,\left(\left(5\cdot\left(x+1\right)\right)+3\cdot\left(2x+1\right)\right)-65=0\)
\(11x-57=0\)
\(11x=57\)
\(x=\frac{57}{11}\)
\(3,\left(\left(3\cdot\left(3x+4\right)\right)+5\cdot\left(2x+1\right)\right)-100=0\)
\(19x-83=0\)
\(19x=83\)
\(x=\frac{83}{19}\)
\(2\times\left(x\times4\right)+5=65\\ 2\times x\times4=65-5\\ x\times8=60\\ x=\dfrac{60}{8}=\dfrac{15}{2}\)
2 x ( X x 4 ) + 5 = 65
2 x ( X x 4 ) = 65 - 5
2 x ( X x 4 ) = 60
X x 4 = 60 : 2
X x 4 = 30
X = 30 : 4
X = 7,5
Vậy X = 7,5