Question

Tìm x:

a, \(\left|x+1\right|+\left|-13\right|=26\\ \)

\(b,\)\(3^{x+2}+3^x=250\)

\(c,\)\(3^{x-1}+5\times3^{x-1}=162\)

\(d,\)\(5^x+5^{x+2}=650\)

Answer 1

a) \(\left|x+1\right|+\left|-13\right|=26\)

\(\left|x+1\right|+13=26\)

\(\left|x+1\right|=26-13\)

\(\left|x+1\right|=13\)

\(\Rightarrow\orbr{\begin{cases}x+1=13\\x+1=-13\end{cases}}\Rightarrow\orbr{\begin{cases}x=12\\x=-14\end{cases}}\)

vậy ........

b) \(3^{x+2}+3^x=250\)

\(3^x.3^2+3^x=250\)

\(3^x.\left(3^2+1\right)=250\)

\(3^x.10=250\)

\(3^x=25\)

\(\Rightarrow x\in\varnothing\) 

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