\(x^2-36=0\Rightarrow x^2=36\) \(\Rightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)
\(3x^2-75=0\)
\(\Rightarrow3\left(x^2-25\right)=0\)
\(\Rightarrow x^2-25=0\Rightarrow x^2=25\) \(\Rightarrow\left[{}\begin{matrix}x=5\\x=-5\end{matrix}\right.\)
\(4x^2-4x+1=0\)
\(\Rightarrow\left(2x-1\right)^2=0\)
\(\Rightarrow2x-1=0\Rightarrow2x=1\Rightarrow x=\dfrac{1}{2}\)
\(\left(x+3\right)^2-4=0\)
\(\Rightarrow\left(x+3\right)^2=4\)
\(\Rightarrow\left[{}\begin{matrix}x+3=2\\x+3=-2\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=-1\\x=-5\end{matrix}\right.\)
a) \(x^2-36=0\Leftrightarrow x^2=36\Leftrightarrow\left[{}\begin{matrix}x=\sqrt{36}\\x=-\sqrt{36}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)
vậy \(x=6;x=-6\)
b) \(3x^2-75=0\Leftrightarrow3\left(x^2-25\right)=0\Leftrightarrow x^2-25=0\Leftrightarrow x^2=25\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\sqrt{25}\\x=-\sqrt{25}\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-5\end{matrix}\right.\) vậy \(x=5;x=-5\)
c) \(4x^2-4x+1=0\Leftrightarrow\left(2x-1\right)^2=0\Leftrightarrow2x-1=0\Leftrightarrow2x=1\)
\(\Leftrightarrow x=\dfrac{1}{2}\) vậy \(x=\dfrac{1}{2}\)
d) \(\left(x+3\right)^2-4=0\Leftrightarrow\left(x+3\right)^2=4\Leftrightarrow\left[{}\begin{matrix}x+3=\sqrt{4}\\x+3=-\sqrt{4}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=2\\x+3=-2\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=-5\end{matrix}\right.\) vậy \(x=-1;x=-5\)
\(a,x^2-36=0\)
\(\Leftrightarrow\left(x-6\right)\left(x+6\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-6=0\\x+6=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)
\(b,3x^2-75=0\)
\(\Leftrightarrow3\left(x^2-25\right)=0\)
\(\Leftrightarrow\left(x-5\right)\left(x+5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-5=0\\x+5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-5\end{matrix}\right.\)
\(c,4x^2-4x+1=0\)
\(\Leftrightarrow\left(2x-1\right)^2=0\)
\(\Leftrightarrow2x-1=0\)
\(\Rightarrow x=\dfrac{1}{2}\)
\(d,\left(x+3\right)^2-4=0\)
\(\Leftrightarrow\left(x+3+2\right)\left(x+3-2\right)=0\)
\(\Leftrightarrow\left(x+5\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+5=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=-1\end{matrix}\right.\)
a, \(x^2-36=0\)
\(x^2=36\)
\(\Rightarrow x=6\)
b, \(3x^2-75=0\)
\(3x^2=75\)
\(x^2=25\)
\(\Rightarrow x=5\)
c, \(4x^2-4x+1=0\)
\(4\left(x^2-x\right)=-1\)
\(\left(x^2-x\right)=\dfrac{-1}{4}\)
\(x\left(x-1\right)=\dfrac{-1}{4}\)
Tự xét nốt nha
d, \(\left(x+3\right)^2=4\)
\(\left(x+3\right)^2=2^2\)
\(\Rightarrow x+3=2\)
\(\Rightarrow x=2-3\)
\(\Rightarrow x=-1\)
