a )
\(\dfrac{27}{3^x}=3\)
\(\Rightarrow3^x=27:3\)
\(\Rightarrow3^x=9\)
\(\Rightarrow3^x=3^2\)
\(\Rightarrow x=2\)
Vậy \(x=2\)
b )
\(9^{x-1}=\dfrac{1}{9}\)
\(\Rightarrow9^{x-1}=9^{-1}\)
\(\Rightarrow x-1=-1\)
\(\Rightarrow x=0\)
Vậy \(x=0\)
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, \(\dfrac{\dfrac{5}{9}}{\left(3x-1\right)^2}=\dfrac{1-2x}{\dfrac{25}{3}}\)
a) Tìm tập hợp các số nguyên x, biết rằng\(4\dfrac{5}{9}:2\dfrac{5}{18}-7< x< \left(3\dfrac{1}{5}:3,2+4,5.1\dfrac{31}{45}\right):\left(-21\dfrac{1}{2}\right)\)
b) tìm x, biết \(\left|x+\dfrac{1}{2}\right|+\left|x+\dfrac{1}{6}\right|+\left|x+\dfrac{1}{12}\right|+\left|x+\dfrac{1}{20}\right|+....+\left|x+\dfrac{1}{110}\right|-11x\)
c)Tính gt biểu thức \(C=2x^3-5y^3+2015\) tại x,y thỏa mãn \(\left|x-1\right|+\left(y+2\right)^{20}=0\)
Tìm x biết
a) \(2.3^x-405=3^{x-1}\)
b) \(\dfrac{x+1}{65}+\dfrac{x+3}{63}=\dfrac{x+5}{61}+\dfrac{x+7}{59}\)
c) \(\left|3x-5\right|=\left|\dfrac{1}{2}x+3\right|\)
d) \(\left(\dfrac{1}{81}\right)^x.27^{2x}=\left(-9\right)^4\)
Tìm x biết:
a) \(\left(x+\dfrac{1}{2}\right)^2=\dfrac{1}{16}\)
b) \(\left(x^4\right)^2=\dfrac{x^{12}}{x^5}\left(x\ne0\right)\)
c) \(\left(2x+3\right)^2=\dfrac{9}{121}\)
d) \(\left(2x-1\right)^3=\dfrac{-8}{27}\)
a) \(\left(\dfrac{1}{5}-\dfrac{3}{2}x\right)^2=\dfrac{9}{4}\)
b) \(\left(3x+1\right)^3=-27\)
c)\(7.3^{x-1}-3^{x+2}=-540\)
Tìm x:
a) 27x .9x = 927:81
b)\(\left(\dfrac{12}{25}\right)^x=\left(\dfrac{5}{3}\right)^{-2}-\left(\dfrac{-3}{5}\right)^4\)
Bài 1: tính
a) \(\dfrac{13}{32}+\dfrac{8}{24}+\dfrac{19}{32}+\dfrac{2}{3}\)
b)\(\dfrac{3}{4}.36\dfrac{1}{5}-\dfrac{3}{4}.2\dfrac{1}{5}\)
c) \(3^4:3.\dfrac{1}{27}\)
d) \(0,1.\sqrt{225}-\sqrt{\dfrac{1}{4}}\)
Bài 2: Tìm x
a) \(\dfrac{9}{5}.x=\dfrac{27}{10}\)
b)\(|x|+1,25=3\)
c) \(\left(2-x\right)^3=25\)
d) \(3^{x-1}+5.3^{x-1}=162\)
Bài 3: tìm x,y biết
\(|x+5|+\left(3y-4\right)^{2018}=0\)
Bài 4: so sánh
\(13\) và \(\sqrt{170}\)
2. tìm x
a. \(\dfrac{x}{3}\)=\(\dfrac{-15}{6}\)
b. \(\dfrac{4}{9}\)+\(\dfrac{7}{3}\):x=\(\dfrac{1}{5}\)
c. \(\dfrac{x}{2}\)=\(\dfrac{-49}{14}\)
d. \(\dfrac{x}{27}\)-\(\dfrac{2}{9}\)=\(\dfrac{-1}{3}\)
e.(x+2,5):\(2\dfrac{1}{2}\)-1,5=\(-1\dfrac{1}{4}\)
a, 4(5x-3)-3(2x+1)=9
b, |x-9|=2x+5
c, \(\dfrac{2}{x-3}+\dfrac{3}{x+3}=\dfrac{3x+5}{x^2-9}\)