Question

[hy pis]

tìm x,biết
(1/2)^x +(1/2)^x +4=17
  

Answer 1

[Nguyễn Vũ Minh Hiếu]

\(\left(\frac{1}{2}\right)^x\)+    \(\left(\frac{1}{2}\right)^{x+4}\)= 17

\(\Rightarrow\)\(\left(\frac{1}{2}\right)^x\)+    \(\left(1+\left(\frac{1^4}{2}\right)\right)\)= 17

\(\Rightarrow\)\(\left(\frac{1}{2}\right)^x\)\(.\frac{17}{16}\)= 17

\(\Rightarrow\)\(\left(\frac{1}{2}\right)^x\)= 16

\(\Rightarrow\)\(\left(\frac{1}{2}\right)^x\)=    \(\left(\frac{1}{2}\right)^{-4}\)

\(\Rightarrow\)\(x=-4\)

Vậy \(x=-4\)