3. How to graph f(x)=-3x^2-1.
4. How to graph f(x)=-2\sqrt{x}.
for both, make a table of values.
I would use -3 to +3 for the first one, and you should get a parabola that opens downwards
for the second, y = -2/√x , clearly we can only use x > 0
pick x's that are perfect squares, such as 1, 4, 9, 16, ...
It should look like this
http://www.wolframalpha.com/input/?i=plot+y+%3D+-2%2F%E2%88%9Ax+,+x+%3E+0
ignore the red part of the graph, use only the blue one