I can describe the reflection of the given triangle across the y-axis, but I can't create graphical representations. When you reflect a shape across the y-axis, you essentially swap the x-coordinates of its points while keeping the y-coordinates the same.
Given the coordinates of your original triangle:
(-2, -9), (7, -4), (9, -7)
The reflected triangle across the y-axis would have these coordinates:
(2, -9), (-7, -4), (-9, -7)
These new coordinates represent the triangle after being reflected across the y-axis.