9x-1=\(\dfrac{1}{9}\)
=>9x-1=9-1
=>x-1=-1
x=-1+1
x=0
\(9^{x-1}=\dfrac{1}{9}\)
\(\Rightarrow9^{x-1}=9^{-1}\)
\(\Rightarrow x-1=-1\)
\(\Rightarrow x=-1+1=0\)
Vậy x = 0
a, 4(5x-3)-3(2x+1)=9
b, |x-9|=2x+5
c, \(\dfrac{2}{x-3}+\dfrac{3}{x+3}=\dfrac{3x+5}{x^2-9}\)
tìm x , biết :
a, \(\dfrac{37-x}{2x+5}=\dfrac{4}{9}\)
b, \(\dfrac{x-2}{x-1}=\dfrac{x+4}{x+7}\)
c, \(\dfrac{x+3}{25}=\dfrac{9}{x+3}\)
d, \(\dfrac{x}{\dfrac{-2}{3}}=\dfrac{5}{-x}\)
e, \(\dfrac{2x-5}{\dfrac{3}{2}}=\dfrac{\dfrac{-27}{8}}{5-2x}\)
f, \(\dfrac{\dfrac{5}{9}}{\left(3x-1\right)^2}=\dfrac{1-2x}{\dfrac{25}{3}}\)
Tìm x, biết:
a) \(\dfrac{27}{3^x}=3\)
b) \(9^{x-1}=\dfrac{1}{9}\)
Tính :
a) \(\left|x-1\right|-\left(-2\right)^3=9.\left(-1\right)^{100}\)
b) \(\dfrac{x-2}{-4}=\dfrac{-9}{x-2}\)
c) \(\dfrac{x-5}{3}=\dfrac{-12}{5-x}\)
Tìm x;y;z biết :
1) \(\dfrac{1+2y}{6}=\dfrac{3+4y}{5}=\dfrac{9+6y}{2x+1}\)
2) \(\dfrac{1+2y}{18}=\dfrac{1+4y}{28}=\dfrac{1+6y}{6x}\)
1. tìm x biết
a. \(1\dfrac{2}{3}\)x-\(\dfrac{1}{4}\)=\(\dfrac{5}{6}\)
b. \(\dfrac{1}{5}\)+x=\(\dfrac{-2}{3}\)
c. |x-\(\dfrac{1}{2}\)|-\(\sqrt{\dfrac{1}{9}}\)=\(\sqrt{\dfrac{1}{4}}\)
d. \(\sqrt{x}\)=9
\(\dfrac{\left(x-1\right)^2}{-3}=\dfrac{9}{x-1}\left(x\ne1\right)\)
Tìm x, biết rằng:
1) ( 2x + 1)3 = -0,001
2) ( 2x -3 )4 = ( 2x-3 )6
3) ( 2x+1 )5 = ( 2x+1)2010
4) \(\dfrac{8}{25}=\dfrac{2^x}{5^{x-1}}\)
5) 9x : 3x = 3
6) \(3^x+3^{x+3}=756\)
7) \(5^{x+1}+6.5^{x+1}=875\)
8) \(2^{x-1}.3^{y+1}=12^{x+9}\)
9) \(3^x=9^{y-1}\)
10) \(2^{x+1}.5^y=20^x\)
11) 15x : 3y = 75y
12) \(\dfrac{3}{5}:\dfrac{2x}{15}=\dfrac{1}{2}:\dfrac{4}{5}\)
13) \(\dfrac{x}{2}=\dfrac{y}{3}=\dfrac{z}{4}\) và xy + yz + zx = 104
\(\dfrac{x}{7}=\dfrac{y}{9}=\dfrac{z}{11}vày-x=-1\)