Question

tim x biet 

a) [x-3].[x+2]=0

b) [x+1] . x < 0

Answer 1

a) (x-3).(x+2)=0

=>x - 3 = 0 hoặc x + 2 = 0

=>x = 3 hoặc x = -2.

Answer 2

a) \(\left(x-3\right)\left(x+2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x-3=0\\x+2=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=3\\x=-2\end{cases}}\)

vay \(\orbr{\begin{cases}x=3\\x=-2\end{cases}}\)

b) \(\left(x+1\right).x< 0\)

\(\Rightarrow\orbr{\begin{cases}x< 0\\x+1< 0\end{cases}}\Rightarrow\orbr{\begin{cases}x< 0\\x< -1\end{cases}}\)

vay \(\orbr{\begin{cases}x< 0\\x< -1\end{cases}}\)