a, \(\left(x-2\right)^3=-27\)
\(\Rightarrow\left(x-2\right)^3=-3^3\)
\(\Rightarrow x-2=-3\)
\(\Rightarrow x=-3+2=-1\)
b, \(\left|3,5-x\right|+\dfrac{2}{7}=\dfrac{16}{7}\)
\(\Rightarrow\left|3,5-x\right|=\dfrac{16}{7}-\dfrac{2}{7}=\dfrac{14}{7}=2\)
\(\Rightarrow\left[{}\begin{matrix}3,5-x=2\\3,5-x=-2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1,5\\x=5,5\end{matrix}\right.\)
\(\left(x-2\right)^3=-27\)
\(\left(x-2\right)^3=-3^3\)
=> \(x-2=-3\)
\(x=-3+\left(-2\right)\)
\(x=-5\)
Vậy x=5
\(\left|3,5-x\right|+\dfrac{2}{7}=\dfrac{16}{7}\)
\(\left|3,5-x\right|=\dfrac{16}{7}-\dfrac{2}{7}\)
\(\left|3,5-x\right|=\dfrac{14}{7}\)
\(\left|3,5-x\right|=2\)
=> \(3,5-x=2hoặc3,5-x=-2\)
\(x=3,5-2\) hoặc \(x=3,5-\left(-2\right)\)
\(x=1,5\) hoặc \(x=3,5+2\)
\(x=1,5\) hoặc \(x=5,5\)
Vậy x=1,5 hoặc x=5,5
\(a)\left(x-2\right)^3=-27\)
\(\Rightarrow\left(x-2\right)^3=-3^3\)
\(\Rightarrow x-2=-3\)
\(\Rightarrow x=-3+2=-1\)
\(b)\left|3,5-x\right|+\dfrac{2}{7}=\dfrac{16}{7}\)
\(\Rightarrow\left|3,5-x\right|=\dfrac{16}{7}-\dfrac{2}{7}\)
\(\Rightarrow\left|3,5-x\right|=2\)
\(\Rightarrow\left[{}\begin{matrix}3,5-x=2\\3,5-x=-2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1,5\\x=5,5\end{matrix}\right.\)
Chúc bạn học tốt!
