a) \(\left(2x-1\right)^3=-27\)
\(\Leftrightarrow\left(2x-1\right)^3=\left(-3\right)^3\)
\(\Leftrightarrow2x-1=-3\)
\(\Leftrightarrow2x=-3+1\)
\(\Leftrightarrow2x=-2\)
\(\Leftrightarrow x=-1\)
b) \(\left(x-3\right)^{10}=\left(x-3\right)^{30}\)
\(\Leftrightarrow\left(x-3\right)^{10}=\left[\left(x-3\right)^{10}\right]^3\)
\(\Leftrightarrow x-3=\left(x-3\right)^3\)
giải ra x = 4 ; x = 2; x = 3
\(\text{a) }\left(2x-1\right)^3=-27\\ \Leftrightarrow\left(2x-1\right)^3=-3^3\\ \Leftrightarrow2x-1=-3\\ \Leftrightarrow2x=-2\\ \Leftrightarrow x=-1\\ \text{Vậy }x=-1\\ \)
\(\text{b) }\left(x-3\right)^{10}=\left(x-3\right)^{30}\\ \Leftrightarrow\left(x-3\right)^{10}-\left(x-3\right)^{30}=0\\ \Leftrightarrow\left(x-3\right)^{10}\left[1-\left(x-3\right)^{20}\right]=0\\ \Leftrightarrow\left[{}\begin{matrix}\left(x-3\right)^{10}=0\\1-\left(x-3\right)^{20}=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x-3=0\\\left(x-3\right)^{20}=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x-3=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=4\end{matrix}\right.\\ \text{Vậy }x=3\text{ hoặc }x=4\)
\(a. (2x-1)^3=-27\)
<=>\((2x-1)^3=-3^3 \)
<=>2x-1=-3
<=>2x=-2
=>x=-1
câu b máy mình ko nhập được sory
