Question

Gấp lm

Answer 1

a) \(4x^2-36=0\)

\(\Leftrightarrow4x^2=36\)

\(\Leftrightarrow x^2=9\)

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

b) \(\left|x-2\right|-4=0\)

\(\Leftrightarrow\left|x-2\right|=4\)

\(\Leftrightarrow\left[{}\begin{matrix}x-2=4\\x-2=-4\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)

Answer 2

\(a,\Rightarrow4\left(x^2-9\right)=0\\ \Rightarrow x^2-9=0\Rightarrow x^2=9\\ \Rightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\\ b,\Rightarrow\left|x-2\right|=4\\ \Rightarrow\left[{}\begin{matrix}x-2=4\left(x\ge2\right)\\2-x=4\left(x< 2\right)\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=6\left(tm\right)\\x=-2\left(tm\right)\end{matrix}\right.\)

Answer 3

a)
\(4x^2-36=0\)
\(4x^2=36\)
\(x^2=18\)
\(x=3\sqrt{2}\)
b)
\(\left|x-2\right|-4=0\)
\(\left|x-2\right|=4\)
x-2=4 hoặc -x+2=4
x=6     hoặc x=-2