ANSWER:
[tex](6,9),(9,1),(12,15)[/tex]STEP-BY-STEP EXPLANATION:
To calculate the new coordinates we must multiply each point by the scale factor, just like this:
[tex]\begin{gathered} (2,3)\rightarrow(3\cdot2,3\cdot3)\rightarrow(6,9) \\ (3,1)\rightarrow(3\cdot3,3\cdot1)\rightarrow(9,1) \\ (4,5)\rightarrow(3\cdot4,3\cdot5)\rightarrow(12,15) \end{gathered}[/tex]