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LH
2
TK
4 tháng 10 2015
(7x - 11)3 = 25 . 52 + 200
(7x - 11)3 = 32 . 25 + 200
(7x - 11)3 = 800 + 200
(7x - 11)3 = 1000
(7x - 11)3 = 103
7x - 11 = 10
7x = 10 + 11
7x = 21
x = 21 : 7
x = 3
4 tháng 10 2015
=>(7x-11)^3=1000
=>\(\left(7x-11\right)^3=10^3\)
=>7x-11=10
=>7x=10+11
=>7x=21
=>x=21:7
=>x=3
NH
1
TN
3
12 tháng 2 2017
\(a,3\frac{1}{3}x+16\frac{3}{4}=-13,25\)
\(\frac{10}{3}x+\frac{67}{4}=-13,25\)
\(\frac{10}{3}x=-13,25-\frac{67}{4}\)
\(\frac{10}{3}x=-30\)
\(x=\left(-30\right):\frac{10}{3}\)
\(x=-9\)
\(b,\left(7x-11\right)^3=2^5.5^2+200\)
\(\left(7x-11\right)^3=32.25+200\)
\(\left(7x-11\right)^3=1000\)
\(\Rightarrow\left(7x-11\right)^3=10^3\)
\(\Rightarrow7x-11=10\)
\(\Rightarrow7x=10+11\)
\(\Rightarrow7x=21\)
\(\Rightarrow x=3\)
12 tháng 2 2017
A) (10/3)x+67/4=-53/4<=>(10/3)x=-53/4-67/4=-30<=>x=-30:(10/3)=-9 b) (7x-11)^3=1000=10^3<=>7x-11=10=>7x=21=>x=3
10 tháng 7 2017
b) Ta có : \(\left(x-\frac{1}{3}\right)^2-\frac{1}{4}=0\)
\(\Rightarrow\left(x-\frac{1}{3}\right)^2=\frac{1}{4}\)
\(\Rightarrow\orbr{\begin{cases}\left(x-\frac{1}{3}\right)^2=\left(\frac{1}{2}\right)^2\\\left(x-\frac{1}{3}\right)^2=\left(-\frac{1}{2}\right)^2\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x-\frac{1}{3}=\frac{1}{2}\\x-\frac{1}{3}=-\frac{1}{2}\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{5}{6}\\x=-\frac{1}{6}\end{cases}}\)
10 tháng 7 2017
b) \(\left(x-\frac{1}{3}\right)^2-\frac{1}{4}=0\)
\(\Leftrightarrow\left(x-\frac{1}{3}\right)^2=\frac{1}{4}\)
\(\Rightarrow\orbr{\begin{cases}x-\frac{1}{3}=\frac{1}{4}\\x-\frac{1}{3}=-\frac{1}{4}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{7}{12}\\x=\frac{1}{12}\end{cases}}\)
d) \(\frac{x+5}{2}=\frac{8}{x+5}\)
\(\Rightarrow\left(x+5\right)^2=16\)
\(\Rightarrow\orbr{\begin{cases}x+5=16\\x+5=-16\end{cases}\Rightarrow\orbr{\begin{cases}x=11\\x=-21\end{cases}}}\)
MV
10 tháng 7 2017
a)
\(x+\left(x-1\right)+\left(x-2\right)+...+\left(x-50\right)=255\\ x+x-1+x-2+...+x-50=255\\ \left(x+x+x+...+x\right)-\left(1+2+3+...+50\right)\\ 51x-1275=255\\ 51x=1530\\ x=30\)
e)
\(x+\left(x+1\right)+\left(x+2\right)+...+\left(x+30\right)=1240\\ x+x+1+x+2+...+x+30=1240\\ \left(x+x+x+...+x\right)+\left(1+2+3+...+30\right)=1240\\ 31x+465=1240\\ 31x=775\\ x=25\)
f)
\(\left(x-1\right)+\left(x-2\right)+...+\left(x-19\right)+\left(x-20\right)=-610\\ x-1+x-2+...+x-19+x-20=-610\\ \left(x+x+x+...+x\right)-\left(1+2+3+...+20\right)=-610\\ 20x-210=-610\\ 20x=-400\\ x=-20\)
QA
22 tháng 8 2021
Trả lời:
\(a,3^{x-1}+5.3^{x-1}=162\)
\(\Rightarrow3^{x-1}.\left(1+5\right)=162\)
\(\Rightarrow3^{x-1}.6=162\)
\(\Rightarrow3^{x-1}=27\)
\(\Rightarrow3^{x-1}=3^3\)
\(\Rightarrow x-1=3\)
\(\Rightarrow x=4\)
Vậy x = 4
\(b,2^{x+5}+2^{x+2}=576\)
\(\Leftrightarrow2^{\left(x+2\right)+3}+2^{x+2}=576\)
\(\Rightarrow2^{x+2}.\left(2^3+1\right)=576\)
\(\Rightarrow2^{x+2}.9=576\)
\(\Rightarrow2^{x+2}=64\)
\(\Rightarrow2^{x+2}=2^6\)
\(\Rightarrow x+2=6\)
\(\Rightarrow x=4\)
Vậy x = 4
c, x = 6
29 tháng 5 2022
a: \(\dfrac{4^5+4^5+4^5+4^5}{3^5+3^5+3^5+3^5}\cdot\dfrac{6^5+6^5+6^5+6^5+6^5+6^5}{2^5+2^5+2^5+2^5+2^5+2^5}=2^x\)
\(\Leftrightarrow2^x=\dfrac{4^5}{3^5}\cdot\dfrac{6^5}{2^5}=4^5=2^{10}\)
=>x=10
b: \(\left(x-1\right)^{x+4}=\left(x-1\right)^{x+2}\)
\(\Leftrightarrow\left(x-1\right)^{x+2}\left[\left(x-1\right)^2-1\right]=0\)
\(\Leftrightarrow x\left(x-1\right)^{x+2}\cdot\left(x-2\right)=0\)
hay \(x\in\left\{0;1;2\right\}\)
c: \(6\left(6-x\right)^{2003}=\left(6-x\right)^{2003}\)
\(\Leftrightarrow5\cdot\left(6-x\right)^{2003}=0\)
\(\Leftrightarrow6-x=0\)
hay x=6
( 7x-1)3=25.52+200
( 7x-1)3=32.25+200
( 7x-1)3=800+200
( 7x-1)3=1000
( 7x-1)3=103
=>7x-1=10
7x=10+1
7x=11
x=11:7
x=11/7
( 7x-1)3=25.52+200
( 7x-1)3=32.25+200
( 7x-1)3=800+200
( 7x-1)3=1000
( 7x-1)3=103
=>7x-1=10
7x=10+1
7x=11
x=11:7
x=11/7