Question

tìm số nguyên x

3^x+2+4.3^x+1=7.3

Answer 1

\(3^{x+2}+4.3^{x+1}=7.3\)

\(\Leftrightarrow3^x\left(3^2+4.3\right)=21\)

\(\Leftrightarrow3^x.21=21\)

\(\Leftrightarrow3^x=1\Leftrightarrow x=0\)

Answer 2

\(3^{x+2}+4.3^{x+1}=7.3\)

\(\Leftrightarrow3^{x+2}+4.3^{x+1}=21\)

\(\Leftrightarrow3^x\left(3^2+4.3\right)=21\)

\(\Leftrightarrow3^x.21=21\Leftrightarrow3^x=1\)

\(\Leftrightarrow x=0\)