When rotating a point 270 degrees counterclockwise about the origin, our point A(x,y) becomes A'(y,-x).
This means, we switch x and y and make x negative.
Before plotting the graph, let's first convert the initial points into its new location after being rotated.
We get,
C (-5, 5) = C' (5, 5)
D (-1, 7) = D' (7, 1)
E (-3, 3) = E' (3, 3)
F (-7, 1) = F' (1, 7)
Let's now plot the graph,