2^x : 3^x = 4/9

=> \(\frac{2}{3}^x=\frac{4}{9}\)

=> \(\frac{2}{3}^x=\frac{2}{3}^2\)

=> x = 2

#)Giải :

\(2^x.3^x=\frac{4}{9}\)

\(2^x.3^x=\left(\frac{2}{3}\right)^2\)

\(\Leftrightarrow x+x=2\)

Có gì đó sai sai ...

\(\frac{1}{7}.\left(\frac{-23}{10}\right)+\frac{77}{10}\)

\(=\frac{-23}{70}+\frac{77}{10}\)

\(=\frac{258}{35}\)

\(\frac{1}{7}.\left(\frac{-23}{10}\right)+\frac{77}{10}\)

= \(\frac{-23}{70}+\frac{77}{10}\)

= \(\frac{258}{35}\)

\(x^2-\frac{3}{5}x=0\)

\(\Rightarrow x\left(x-\frac{3}{5}\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x-\frac{3}{5}=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=0\\x=\frac{3}{5}\end{cases}}\)

=.= hk tốt!!

\(x^2-\frac{3}{5}x=0\)

=> \(x\left(x-\frac{3}{5}\right)=0\)

=> \(\orbr{\begin{cases}x=0\\x-\frac{3}{5}=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=0+\frac{3}{5}\end{cases}\Rightarrow}\orbr{\begin{cases}x=0\\x=\frac{3}{5}\end{cases}}}\)

Vậy x = 0 hoặc x = \(\frac{3}{5}\)

#)Giải :

\(\left(\frac{3}{4}-\frac{13}{11}+\frac{7}{5}\right)-\left(3-\frac{1}{2}-\frac{35}{11}\right)+\left(\frac{11}{4}-\frac{2}{5}\right)\)

\(=\frac{3}{4}-\frac{13}{11}+\frac{7}{5}-3+\frac{1}{2}+\frac{35}{11}-\frac{11}{4}+\frac{2}{5}\)

\(=\left(\frac{3}{4}-\frac{11}{4}\right)+\left(-\frac{13}{11}+\frac{35}{11}\right)+\left(\frac{7}{5}+\frac{2}{5}\right)-3+\frac{1}{2}\)

\(=-2+2+\frac{9}{5}-3+\frac{1}{2}\)

\(=\frac{9}{5}-3+\frac{1}{2}\)

\(=-\frac{7}{10}\)

#)Giải :

a) \(\left|2x-3\right|-\frac{1}{3}=0\)

\(\Leftrightarrow\left|2x-3\right|=-\frac{1}{3}\)

\(\orbr{\begin{cases}2x>3\\2x< 3\end{cases}\Rightarrow\orbr{\begin{cases}2x-3=-\frac{1}{3}\\3-2x=-\frac{1}{3}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{8}{3}\\x=\frac{10}{3}\end{cases}}}\)

a) |2x - 3| - 1/3 = 0

=>|2x - 3|         = 0 + 1/3

=>|2x - 3|         = 1/3

=> \(\orbr{\begin{cases}2x-3=\frac{1}{3}\\2x-3=-\frac{1}{3}\end{cases}}\)         => \(\orbr{\begin{cases}2x=\frac{1}{3}+3\\2x=-\frac{1}{3}+3\end{cases}}\)=> \(\orbr{\begin{cases}2x=\frac{10}{3}\\2x=\frac{8}{3}\end{cases}}\)=> \(\orbr{\begin{cases}x=\frac{10}{3}:2\\x=\frac{8}{3}:2\end{cases}}\)=>\(\orbr{\begin{cases}x=\frac{5}{3}\\x=\frac{4}{3}\end{cases}}\)

b) 5/6 - |x + 1/4| = 1/4

=>        |x + 1/4| = 5/6 - 1/4

=>        |x + 1/4| = 7/12

=> \(\orbr{\begin{cases}x+\frac{1}{4}=\frac{7}{12}\\x+\frac{1}{4}=-\frac{7}{12}\end{cases}}\)=> \(\orbr{\begin{cases}x=\frac{7}{12}-\frac{1}{4}\\x=-\frac{7}{12}-\frac{1}{4}\end{cases}}\)=> \(\orbr{\begin{cases}x=\frac{1}{3}\\x=\frac{-5}{6}\end{cases}}\)

trả lời

=19,8.10.2,4+19,8.2,2+19.8:10 .54

=19,8.24+29,8.2,2+19,8.54

=19,8.76,2=1508,76

158796

\(x^2-3x=0\)

\(\Rightarrow x\left(x-3\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x-3=0\end{cases}\Rightarrow}\orbr{\begin{cases}x=0\\x=3\end{cases}}\)

Vậy..

trả lời

x^2+3x=0

<=>x(x+3)=0

th1:x=0

th2:x+3=0=>x=-3

vậy x=0 hoặc -3

a) \(3n+5⋮n+4\)

\(\Rightarrow3.\left(n+4\right)-7⋮n+4\)

Mà \(3.\left(n+4\right)⋮n+4\)

\(\Rightarrow7⋮n+4\)

Tự tìm nốt

b) \(n^2+5⋮n+1\)

\(\Rightarrow n^2+n-n+5⋮n+1\)

\(\Rightarrow n.\left(n+1\right)-\left(n-5\right)⋮n+1\)

mà \(n.\left(n+1\right)⋮n+1\)

\(\Rightarrow n-5⋮n+1\)

\(\Rightarrow n+1-6⋮n+1\)

mà \(n+1⋮n+1\)

\(\Rightarrow6⋮n+1\)

Tìm nốt

Vẽ hình thôi nhé

CÁI đó ai chẳng biết

a) \(\frac{x}{5}=\frac{2}{3}\Rightarrow3x=5.2\)

\(\Rightarrow3x=10\)

\(\Rightarrow x=10:3\)

\(\Rightarrow x=\frac{10}{3}\)

b) x + 3/15 = 1/3

=> x            = 1/3 - 3/15

=> x            = 2/15

c) x - 12/4 = 1/2

=> x           = 1/2 + 12/4

=> x            = 7/2

#) Giải

a. \(\frac{x}{5}=\frac{2}{3}\)

\(\frac{x.3}{15}=\frac{10}{15}\)

\(x.3=10\)

\(x=\frac{10}{3}\)

b.  \(x=\frac{1}{3}-\frac{3}{15}=\frac{2}{15}\)

c. \(x=\frac{1}{2}+\frac{12}{4}=\frac{7}{2}\)

~ Hok tốt ~