Question

/x(\(x^2\)-\(\dfrac{5}{4}\))/ tìm x

Answer 1

/x(x^2-5/4)/=x
vì /x(x^2-5/4)/ lớn hơn hoặc bằng 0
=>x lớn hơn hoặc bằng 0
=.> x(x^2-5/4)=x
=> x^3-5/4x=x
=> x^3=9/4x
=> x^3-9/4x=0
=> x(x^2-9/4)=0
=>\(\left[{}\begin{matrix}x=0\\x^2-\dfrac{9}{4}=0\end{matrix}\right.=>\left[{}\begin{matrix}x=0\\x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)