a/ \(\dfrac{1}{3}+\dfrac{1}{2}:x=4\)
\(\Leftrightarrow\dfrac{1}{3}+\dfrac{1}{2x}=4\)
\(\Leftrightarrow\dfrac{1}{2x}=\dfrac{11}{3}\)
\(\Leftrightarrow22x=3\)
\(\Leftrightarrow x=\dfrac{3}{22}\)
Vậy ...
b/ \(\left(x-1\right)^3=27\)
\(\Leftrightarrow\left(x-1\right)^3=3^3\)
\(\Leftrightarrow x-1=3\)
\(\Leftrightarrow x=4\)
Vậy ...
c/ \(\left(2x+1\right)^2=16\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(2x+1\right)^2=4^2\\\left(2x+1\right)^2=\left(-4\right)^2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+1=4\\2x+1=-4\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{5}{2}\end{matrix}\right.\)
Vậy..
d/ \(\dfrac{x+3}{2}=\dfrac{3}{5}\)
\(\Leftrightarrow5\left(x+3\right)=6\)
\(\Leftrightarrow5x+15=6\)
\(\Leftrightarrow x=-\dfrac{9}{5}\)
Vậy..
