Question

a ) (-\(\)\(\dfrac{4}{3}\)x + \(\dfrac{1}{2}\))² = \(\dfrac{1}{4}\)

b) 3 ^x + 3 ^x+2= 20

c) ( \(\dfrac{1}{2}\)) ^x+ (\(\dfrac{1}{2}\))^x+2= \(\dfrac{5}{4}\)

Giúp mk với !!! Ngày mai mk làm kiểm tra rồi !!! PLEASE

 

Answer 1

\(a,\Leftrightarrow\left[{}\begin{matrix}-\dfrac{4}{3}x+\dfrac{1}{2}=\dfrac{1}{2}\\-\dfrac{4}{3}x+\dfrac{1}{2}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{3}{4}\end{matrix}\right.\\ c,\Leftrightarrow\left(\dfrac{1}{2}\right)^x\left(1+\dfrac{1}{4}\right)=\dfrac{5}{4}\\ \Leftrightarrow\left(\dfrac{1}{2}\right)^x=1\Leftrightarrow x=0\)

Answer 2

b: Ta có: \(3^x+3^{x+2}=20\)

\(\Leftrightarrow3^x\cdot10=20\)

\(\Leftrightarrow3^x=2\left(loại\right)\)