a) (2x-1)(x+2)=0
<=> 2x-1=0
Hoặc x+2=0
<=>2x=1
Hoặc x=-2
<=>x=1/2
Hoặcx=-2
Xl nha mk ko bt làm mấy câu kia
b) (x-3)3=27
<=>(x-3)3=33
<=>x-3=3
<=>x=6
mn giúp mình với
a, (2x - 1) (x + 2) = 0
⇔\(\left[{}\begin{matrix}2x-1=0\\x+2=0\end{matrix}\right.\)
⇔\(\left[{}\begin{matrix}2x=0+1\\x=0+2\end{matrix}\right.\)
⇔\(\left[{}\begin{matrix}2x=1\\x=2\end{matrix}\right.\)
⇔\(\left[{}\begin{matrix}x=2\\x=2\end{matrix}\right.\)
b,\(\left(x-3\right)^3=27\)
\(\left(x-3\right)^3=3^3\)
\(x-3=3\)
\(x=3+3\)
⇒\(x=6\)