Tìm x biết: 4/11<x/20<5/11
Ai nhanh mk tick. Ths
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18 tháng 8 2021
Bài 1:
Ta có: \(4-2\left(x+1\right)=2\)
\(\Leftrightarrow2\left(x+1\right)=2\)
\(\Leftrightarrow x+1=1\)
hay x=0
Bài 2:
Ta có: \(\left|2x-3\right|-1=2\)
\(\Leftrightarrow\left|2x-3\right|=3\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-3=3\\2x-3=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=6\\2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=0\end{matrix}\right.\)
17 tháng 8 2016
Mình nghĩ bạn chép sai đề rồi. Hãy kiểm tra và sửa lại đề nhé
NT
5
12 tháng 8 2016
\(4^{x+3}-3.4^{x+1}=13.4^{11}\)
\(\Rightarrow4^{x+1}.\left(4^2-3\right)=13.4^{11}\)
\(\Rightarrow4^{x+1}.\left(16-3\right)=13.4^{11}\)
\(\Rightarrow4^{x+1}.13=13.4^{11}\)
\(\Rightarrow x+1=11\)
\(\Rightarrow x=11-1\)
\(\Rightarrow x=10\)
IM
12 tháng 8 2016
\(\Rightarrow4^x\left(4^3-3.4\right)=13.4^{11}\)
\(\Rightarrow4^x.52=13.4^{11}\)
\(\Rightarrow4^x=4^{\left(-1\right)}.4^{11}\)
\(\Rightarrow4^x=4^{10}\)
=> x=10
PA
1 tháng 6 2016
a.
\(\left(\frac{11}{12}+\frac{11}{12\times23}+\frac{11}{23\times34}+...+\frac{11}{89\times100}\right)+x=\frac{2}{3}\)
\(\left(\frac{11}{12}+\frac{1}{12}-\frac{1}{23}+\frac{1}{23}-\frac{1}{34}+...+\frac{1}{89}-\frac{1}{100}\right)+x=\frac{2}{3}\)
\(\left(\frac{11}{12}+\frac{1}{12}-\frac{1}{100}\right)+x=\frac{2}{3}\)
\(\left(\frac{12}{12}-\frac{1}{100}\right)+x=\frac{2}{3}\)
\(\left(1-\frac{1}{100}\right)+x=\frac{2}{3}\)
\(\left(\frac{100-1}{100}\right)+x=\frac{2}{3}\)
\(\frac{99}{100}+x=\frac{2}{3}\)
\(x=\frac{2}{3}-\frac{99}{100}\)
\(x=\frac{200-297}{300}\)
\(x=-\frac{97}{300}\)
b.
\(\left(\frac{2}{11\times13}+\frac{2}{13\times15}+...+\frac{2}{19\times21}\right)-x+\frac{221}{231}=\frac{4}{3}\)
\(\left(\frac{1}{11}-\frac{1}{13}+\frac{1}{13}-\frac{1}{15}+...+\frac{1}{19}-\frac{1}{21}\right)+\frac{221}{231}-x=\frac{4}{3}\)
\(\left(\frac{1}{11}-\frac{1}{21}\right)+\frac{221}{231}-x=\frac{4}{3}\)
\(\left(\frac{21-11}{231}\right)+\frac{221}{231}-x=\frac{4}{3}\)
\(\frac{10}{231}+\frac{221}{231}-x=\frac{4}{3}\)
\(\frac{231}{231}-x=\frac{4}{3}\)
\(1-x=\frac{4}{3}\)
\(x=1-\frac{4}{3}\)
\(x=\frac{3-4}{3}\)
\(x=-\frac{1}{3}\)
Chúc bạn học tốt
VD
2
29 tháng 7 2015
( 4,5 - 2.x ) . 11/7 = 11/14
4,5 - 2.x = 11/14 : 11/7= 1/2
2.x = 4,5 - 1/2 =4
x = 4:2=2
MH
29 tháng 7 2015
\(\left(4,5-2x\right).1\frac{4}{7}=\frac{11}{14}\)
\(\Rightarrow\left(4,5-2x\right).\frac{11}{7}=\frac{11}{14}\)
\(\Rightarrow4,5-2x=\frac{11}{14}:\frac{11}{7}\)
\(\Rightarrow4,5-2x=\frac{11}{14}.\frac{7}{11}\)
\(\Rightarrow4,5-2x=\frac{1}{2}\)
\(\Rightarrow2x=4,5-\frac{1}{2}\)
\(\Rightarrow2x=4,5-0,5\)
\(\Rightarrow2x=4\)
\(\Rightarrow x=4:2\)
\(\Rightarrow x=2\)
VN
5
3 tháng 1 2019
\(|x-11|+x-11=0\)
\(|x-11|+x=11+0\)
\(|x-11|+x=11\)
\(x=11-11\)
\(x=0\)
Hk tốt,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
k nhé
UN
4
12 tháng 8 2016
\(4^{x+3}-3.4^{x+1}=13.4^{11}\)
\(16.4^{x+1}-3.4^{x+1}=13.4^{11}\)
\(\left(16-3\right).4^{x+1}=13.4^{11}\)
\(13.4^{x+1}=13.4^{11}\)
\(\Rightarrow x+1=11\)
\(x=10\)
12 tháng 8 2016
\(4^{x+3}-3.4^{x+1}=13.4^{11}\)
=> \(4^{x+1}.\left(4^2-3\right)=13.4^{11}\)
=> \(4^{x+1}.\left(16-3\right)=13.4^{11}\)
=> \(4^{x+1}.13=13.4^{11}\)
=> \(x+1=11\)
=> \(x=11-1=10\)
10 tháng 8 2016
a, 11/12 - ( 2/5 + x ) = 2/3
<=> \(\frac{2}{5}+x=\frac{11}{12}-\frac{2}{3}=\frac{1}{4}\)
=> x=\(\frac{1}{4}-\frac{11}{12}=-\frac{2}{3}\)
b, 2x . ( x - 1/7 ) = 0
<=>\(\left[\begin{array}{nghiempt}x=0\\x-\frac{1}{7}=0\end{array}\right.\)<=> \(\left[\begin{array}{nghiempt}x=0\\x=\frac{1}{7}\end{array}\right.\)
vậy x={\(0;\frac{1}{7}\)}
c, 3/4 + 1/4 : x = 2/5
<=>\(\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}=-\frac{7}{20}\)
<=> \(x=\frac{1}{4}:\left(-\frac{7}{20}\right)=-\frac{5}{7}\)
vậy x=-5/7
10 tháng 8 2016
a) \(\frac{11}{12}-\left(\frac{2}{5}+x\right)=\frac{2}{3}\)
\(\Leftrightarrow\frac{11}{12}-\frac{2}{5}-x=\frac{2}{3}\)
\(\Leftrightarrow-x=\frac{2}{3}-\frac{11}{12}+\frac{2}{5}=\frac{3}{20}\)
\(\Leftrightarrow x=-\frac{3}{20}\)
b) \(2x\left(x-\frac{1}{7}\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x-\frac{1}{7}=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=0\\x=\frac{1}{7}\end{array}\right.\)
c) \(\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
\(\Leftrightarrow\frac{1}{4x}=\frac{2}{5}-\frac{3}{4}=-\frac{7}{20}\)
\(\Leftrightarrow4x=\frac{-20}{7}\)
\(\Leftrightarrow x=-\frac{5}{7}\)
80/220 < 11x/220 < 100/220
=> 11x = 88 ; 99
=> x=8;9
ngu nham de bai roi em me