Question

Tìm x, biết:

a) \({2^x} = 8;\)                  

b) \({2^x} = \frac{1}{4};\)                         

c) \({2^x} = \sqrt 2 .\)

Answer 1

\(a,2^x=8\\ \Leftrightarrow2^x=2^3\\ \Leftrightarrow x=3\\ b,2^x=\dfrac{1}{4}\\ \Leftrightarrow2^x=2^{-2}\\ \Leftrightarrow x=-2\\ c,2^x=\sqrt{2}\\ \Leftrightarrow2^x=2^{\dfrac{1}{2}}\\ \Leftrightarrow x=\dfrac{1}{2}\)