Question

Thực hiện phép tính: (x - 1/2)(x + 1/2)(4x - 1)

 

Answer 1

\(\left(x-\frac{1}{2}\right)\left(x+\frac{1}{2}\right)\left(4x-1\right)\)

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

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

\(=4x^3-x^2-x+\frac{1}{4}\)

Answer 2

ta có: (x - 1/2)(x + 1/2)(4x - 1) = 0

=> (x² - 1/4)(4x - 1) = 0

=> \(\hept{\begin{cases}x^2-\frac{1}{4}=0\\4x-1=0\end{cases}}\)

=> \(\hept{\begin{cases}x^2=\frac{1}{4}\\4x=1\end{cases}}\)

=> \(\hept{\begin{cases}x=\frac{1}{2}hoặc-\frac{1}{2}\\x=\frac{1}{4}\end{cases}}\)

ok nhé!! 364565467567776892512352534534534564654645645645756756