Answer:
see attached (red)
Explanation:
You want the graph of the transformed triangle defined by the lines y=x, x=6, y=-1/3x+4 after rotation 270° and reflection across the y-axis.
Triangle
A graph of the lines shows the vertices of the triangle are ...
A(3, 3), B(6, 6), C(6,2)
Transformations
Rotation 270° is described by the transformation ...
(x, y) ⇒ (y, -x)
Reflection across the y-axis is described by ...
(x, y) ⇒ (-x, y)
Then the composition of these transformations is ...
(x, y) ⇒ (-y, -x) . . . . . . . . equivalent to reflection over y=-x
Application
Applying this composition to the triangle vertices, we find its final location to be ...
A(3, 3) ⇒ A''(-3, -3)
B(6, 6) ⇒ B''(-6, -6)
C(6,2) ⇒ C''(-2, -6)
The triangle with these vertices is shown in red in the attachment.