Question

Tìm x: biết 2^x . 4^x+1 = 8

Answer 1

\(2^x.4^{x+1}=8\)

\(2^x.4^x.4=8\)

\(\left(2.4\right)^x.4=8\)

\(8^x.4=8\)

\(8^x=8:4\)

\(\left(2^3\right)^x=2\)

\(2^{3x}=2\)

\(\Rightarrow3x=1\)

\(x=1:3\)

\(x=\frac{1}{3}\)

Answer 2

\(2^x.4^{x+1}=8\)

\(=>2^x.\left(2^2\right)^{x+1}=2^3\)

=>\(2^x.2^{2\left(x+1\right)}=2^3\)

\(=>x+2\left(x+1\right)=3\)\(=>x+2x+2=3\)

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

\(=>3x=1\)\(Vậyx=\frac{1}{3}\)