Question

tìm x

(1/2)^x + (1/2)^x + (1/2)^1 = 3/8

giải nhanh giúp mình đang cần gấp, mình cảm ơn ạ

Answer 1

\(\left(\dfrac{1}{2}\right)^x+\left(\dfrac{1}{2}\right)^x+\left(\dfrac{1}{2}\right)^1=\dfrac{3}{8}\)

=>\(\left(\dfrac{1}{2}\right)^x\cdot2=\dfrac{3}{8}-\dfrac{1}{2}=-\dfrac{1}{8}\)

=>\(\left(\dfrac{1}{2}\right)^x=-\dfrac{1}{16}\)(vô lý)

=>\(x\in\varnothing\)

Answer 2

\(\left(\dfrac{1}{2}\right)^x+\left(\dfrac{1}{2}\right)^x+\left(\dfrac{1}{2}\right)^1=\dfrac{3}{8}\)

\(\Leftrightarrow2.\left(\dfrac{1}{2}\right)^x=-\dfrac{1}{8}\)

\(\Leftrightarrow\left(\dfrac{1}{2}\right)^x=-\dfrac{1}{16}\)

=> Vô nghiệm