(2x - 15)mũ 5 = 2x - 15) mũ 3
giải nhanh giúp mình nhé
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Ta có : \(\left(2x-15\right)^5=\left(2x-15\right)^3\)
\(\Rightarrow\left(2x-15\right)^5-\left(2x-15\right)^3=0\)
\(\Rightarrow\left(2x-15\right)^3\left[\left(2x-15\right)^2-1\right]=0\)
\(\Leftrightarrow\orbr{\begin{cases}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x-15=0\\\left(2x-15\right)^2=1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x=15\\2x-15=1;-1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{15}{2}\\2x=16;14\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{15}{2}\\x=8;7\end{cases}}\)
\(\Rightarrow\left(2x-15\right)^5=\left(2x-15\right)^3=0\)
\(\Rightarrow\left(2x-15\right)^3\left[\left(2x-15\right)^2-1\right]=0\)
\(\Leftrightarrow\orbr{\begin{cases}\left(2x-15\right)^3=0\\\left(2x-15\right)^2-1=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x-15=0\\\left(2x-15\right)^2=1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}2x=15\\2x-15=1;-1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=7,5\\x=8;7\end{cases}}\)
\(105-\left[\left(2x+7\right)-13\right]=\left(-15\right)^{10}:\left(9^5.5^8\right)\\ 105-\left[\left(2x+7\right)-13\right]=25\\ \left(2x+7\right)-13=105-25\\ \left(2x+7\right)-13=80\\ 2x+7=80+13\\ 2x+7=93\\ 2x=93-7\\ 2x=86\\ x=\dfrac{86}{2}\\ x=43\)
\(105-\left[\left(2x+7\right)-13\right]=\left(-15\right)^{10}:\left(9^5.5^8\right)\\ 105-\left[\left(2x+7\right)-13\right]=15^{10}:3^{10}:5^8\\ 105-\left[\left(2x+7\right)-13\right]=5^{10}:5^8\\ 105-\left[\left(2x+7\right)-13\right]=25\\ \left(2x+7\right)-13=105-25\\ \left(2x+7\right)-13=80\\ 2x+7=80+13\\ 2x+7=93\\ 2x=93-7\\ 2x=86\\ x=86:2\\ x=43\)
1. 2x=16\(\Rightarrow\)X=4
2. 22x-1=27
\(\Rightarrow\)27=22.4-1
Vậy x =4
(2x - 15)5 = (2x-15)3
<=> (2x-15) = 0 hoặc (2x-15) = 1
+ TH1: (2x-15)5 = (2x-15)3
05 = 03 = 0
+ TH2: (2x-15)5 = (2x-15)3
15 = 13 = 1
\(\left(2x-15\right)^5=\left(2x-15\right)^3\)
\(\left(2x-15\right)^5-\left(2x-15\right)^3=0\)
\(\left(2x-15\right)^3\cdot\left[\left(2x-15\right)^2-1\right]=0\)
\(\hept{\begin{cases}2x-15=0\\\left(2x-15\right)^2-1=0\end{cases}\Rightarrow\hept{\begin{cases}x=\frac{15}{2}\\\left(2x-15\right)^2=1\end{cases}}}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{15}{2}\\\hept{\begin{cases}2x-15=1\\2x-15=-1\end{cases}\Rightarrow\hept{\begin{cases}x=8\\x=7\end{cases}}}\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{15}{2}\\\hept{\begin{cases}2x-15=1\\2x-15=-1\end{cases}}\Rightarrow\hept{\begin{cases}x=8\\x=7\end{cases}}\end{cases}}\)