what would be a good window for the graph of f(x) = -x^5 + 5x^3 - 3x + 15
I think that -10< x<10: -10<y<25 would be good. Does this seem right?
your range for the y values is totally insufficient.
when x = -10, y is around 100000, when x = 10 y is around -100000
You will have to scale the y axis.