ANSWER
L'(1, 2), M'(1, -2), N'(3, 2)
EXPLANATION
The rule for rotating a point (x, y) 90° clockwise is,
[tex](x,y)\rightarrow(y,-x)[/tex]So, the vertices of triangle LMN will be mapped to,
[tex]\begin{gathered} L(-2,1)\rightarrow L^{\prime}(1,2) \\ M(2,1)\rightarrow M^{\prime}(1,-2) \\ N(-2,3)\rightarrow N^{\prime}(3,2) \end{gathered}[/tex]Hence, the image has vertices L'(1, 2), M'(1, -2), N'(3, 2).