Question

[Hiếu Hà Quang]

4.3^2x-2.9^x-54=0

\(\dfrac{1}{2}\).2^x+4,2^x-288=0

Answer 1

[Đức Hiếu]

a, \(4.3^{2x}-2.9^x-54=0\)

\(\Rightarrow3^{2x}\left(4-2\right)=54\)

\(\Rightarrow3^{2x}=27=3^3\)

Vì \(3\ne\pm1;3\ne0\) nên \(2x=3\Rightarrow x=\dfrac{3}{2}\)

b, \(\dfrac{1}{2}.2^x+4.2^x-288=0\)

\(\Rightarrow2^x\left(\dfrac{1}{2}+4\right)=288\)

\(\Rightarrow2^x=64=2^6\)

Vì \(2\ne\pm1;2\ne0\) nên \(x=6\)