Question

2 mũ x + 5.2 mũ x+2 = 168

Answer 1

\(2^x+5\cdot2^{x+2}=168\)

=>\(2^x+20\cdot2^x=168\)

=>\(21\cdot2^x=168\)

=>\(2^x=8=2^3\)

=>x=3

Answer 2

\(2^x+5.2^{x+2}=168\\ \Leftrightarrow2^x.\left(1+5.2^2\right)=168\\ \Leftrightarrow2^x.21=168\\ \Leftrightarrow2^x=\dfrac{168}{21}=8=2^3\\ Vây:x=3\)