Question

Tìm x:

a)(x³-x²) - 4x² +8x - 4 = 0

b) 16x - 5x² - 3 = 0

Bài 2: PTĐTTNT

(x² +1)-x(a² +1)

Answer 1

Tìm x

b) 16x - 5x² - 3 = 0

\(\Leftrightarrow\) 5x² - 16x + 3 = 0

\(\Leftrightarrow\) 5x² - 15x - x + 3 = 0

\(\Leftrightarrow\) ( 5x² - 15x ) - ( x - 3 ) = 0

\(\Leftrightarrow\) 5x ( x - 3 ) - ( x- 3 ) = 0

\(\Leftrightarrow\) ( x - 3 ) ( 5x - 1 ) = 0

\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\5x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=\dfrac{1}{5}\end{matrix}\right.\)

Vậy phương trình có nghiệm x = 3 hoặc x = \(\dfrac{1}{5}\)