Question

Cho A = [ m ; 3m+2 ] ; B = [-2;1]

 Tìm m để A giao B khác rỗng

Answer 1

\(A\cap B\ne\varnothing\Rightarrow\left\{{}\begin{matrix}m\le1\\3m+2\ge-2\end{matrix}\right.\)

\(\Rightarrow-\dfrac{4}{3}\le m\le1\)