a, \(x^3-0,25x=0\)
\(\Leftrightarrow x\left(x^2-0,25\right)=0\)
\(\Leftrightarrow x\left(x-0,5\right)\left(x+0,5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=0,5\\x=-0,5\end{matrix}\right.\)
Vậy...
b, \(4x^2-9=0\)
\(\Leftrightarrow\left(2x-3\right)\left(2x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{-3}{2}\end{matrix}\right.\)
Vậy...
c, \(x^2-10x=-25\)
\(\Leftrightarrow x^2-10x+25=0\)
\(\Leftrightarrow\left(x-5\right)^2=0\Leftrightarrow x=5\)
Vậy...
a) \(x^3-0,25x=0\)
\(\Leftrightarrow x\left(x^2-0,25\right)=0\)
\(\Leftrightarrow x\left(x-0,5\right)\left(x+0,5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x-0,5=0\\x+0,5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=0,5\\x=-0,5\end{matrix}\right.\)
Vậy \(x_1=0;x_2=0,5;x_3=-0,5\).
b) \(4x^2-9=0\)
\(\Leftrightarrow\left(2x-3\right)\left(2x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-3=0\\2x+3=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2x=3\\2x=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)
Vậy \(x_1=\dfrac{3}{2};x_2=-\dfrac{3}{2}\).
c) \(x^2-10x=-25\)
\(\Leftrightarrow x^2-10x+25=0\)
\(\Leftrightarrow\left(x-5\right)^2=0\)
\(\Leftrightarrow x-5=0\Leftrightarrow x=5\)
Vậy x = 5.
a) x3 - 0,25x = 0
=> x ( x2 - 0,25 ) = 0
=> \(\left[{}\begin{matrix}x=0\\x^2-0,25=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x^2=0,25\Rightarrow x=\pm0,5\end{matrix}\right.\)
b) 4x2 - 9 = 0
=> 4x2 = 9
=> x2 = \(\dfrac{9}{4}\)
=> \(x=\pm\dfrac{3}{2}\)
c) x2 - 10x = -25
=> x2 - 10 + 25 = 0
=> ( x - 5 )2 = 0
\(\Rightarrow x-5=0\Rightarrow x=5\)
\(x^3-0,25x=0\)
\(\Rightarrow x\left(x^2-0,25\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x^2-0,25=0\Rightarrow x^2=0,25\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=\pm0,5\end{matrix}\right.\)
\(4x^2-9=0\)
\(\Rightarrow4x^2-3^2=0\)
\(\Rightarrow\left(2x+3\right)\left(2x-3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2x+3=0\Rightarrow2x=-3\\2x-3=0\Rightarrow2x=3\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=\dfrac{3}{2}\end{matrix}\right.\)
\(x^2-10x=-25\)
\(\Rightarrow x^2-10x+25=0\)
\(\Rightarrow\left(x-5\right)^2=0\)
\(\Rightarrow x=5\)
