`6A`
\(a,\left(x-2,5\right)^2=9\\ \Rightarrow\left(x-2,5\right)^2=3^2\\ \Rightarrow\left[{}\begin{matrix}x-2,5=3\\x-2,5=-3\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=5,5\\x=-0,5\end{matrix}\right.\)
\(b,\left(1-x\right)^3=-8\\ \Rightarrow\left(1-x\right)^3=-2^3\\ \Rightarrow1-x=-2\\ \Rightarrow x=1+2\\ \Rightarrow x=3\\ c,2^{4-x}=16\\ \Rightarrow2^{4-x}=2^4\\ \Rightarrow4-x=4\\ \Rightarrow x=4-4\\ \Rightarrow x=0\)
Bài `6B`
\(a,\left(5+x\right)^3=-27\\ \Rightarrow\left(5+x\right)^3=-3^3\\ \Rightarrow5+x=-3\\ \Rightarrow x=-3-5\\ \Rightarrow x=-8\)
\(b,\left(1-x\right)^2=\dfrac{1}{9}\\ \Rightarrow\left(1-x\right)^2=\left(\dfrac{1}{3}\right)^2\\ \Rightarrow\left[{}\begin{matrix}1-x=\dfrac{1}{3}\\1-x=-\dfrac{1}{3}\end{matrix}\right.\\ \Rightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=\dfrac{4}{3}\end{matrix}\right.\)
\(c,5^{3+x}=125\\ \Rightarrow5^{3+x}=5^2\\ \Rightarrow3+x=2\\ \Rightarrow x=2-3\\ \Rightarrow x=-1\)
c tách ra nhé^^
