\(\left(2x+3\right)^4=625\)
\(\left(2x+3\right)^4=5^4\)
\(\Rightarrow2x+3=5\)
\(2x=5-3\)
\(2x=2\)
\(x=2\div2\)
\(x=1\)
\(\left(3x+1\right)^3=343\)
\(\left(3x+1\right)^3=7^3\)
\(3x+1=7\)
\(3x=7-1\)
\(3x=6\)
\(x=6\div3\)
\(x=2\)
bé nguyên sai rồi câu a ấy . câu đấy có hai trường hợp vì nó mũ chẵn nha bạn
\(\left(2x+3\right)^4=625\)
\(\left(2x+3\right)^4-625=0\)
\(\left(2x+3\right)^4-5^4=0\)
\(\left[\left(2x+3\right)^2-25\right]\left[\left(2x+3\right)^2+25\right]=0\)
Ta có : \(\left(2x+3\right)^2+25>0\)
\(\Rightarrow\left[\left(2x+3\right)^2-25\right]=0\)
\(\Leftrightarrow\left(2x+3-5\right)\left(2x+3+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}2x-2=0\\2x+8=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=1\\x=-4\end{cases}}\)
