Question

Tìm x :

  a) \(3^{x+1}\)=\(9^x\)

  b)  \(2^{3x+2}\) = \(4^{x+5}\)

Answer 1

a)
\(3^{x+1}=3^{2x}\)
x+1=2x
x-2x=-1
x=-x=-1
x=1
b)\(2^{3x+2}=2^{2\left(x+5\right)}\)
3x+2=2(x+5)
3x+2=2x+10
x=8

Answer 2

a) \(3^{x+1}=9^x\)

\(\Leftrightarrow3^{x+1}=3^{2x}\)

\(\Leftrightarrow x+1=2x\)

\(\Leftrightarrow x=1\)

b) \(2^{3x+2}=4^{x+5}\)

\(\Leftrightarrow2^{3x+2}=2^{2x+10}\)

\(\Leftrightarrow3x+2=2x+10\)

\(\Leftrightarrow x=8\)