The answers are...
x=7
y=2
You seem to have forgotten to add in the y-intercept or slope. For the information you have given, it could be any equation, so long as it passes through the point (2, -1), such as
y = -x + 1
Here are all the correct answers in the order they are asked.
1. Sphere - all the points from the center create a rounded space
2. Triangular pyramid - A triangular base and three triangular lateral faces
3. Cube all six faces are squares
4. Triangular prism - two triangular bases and four rectangular lateral faces
5. Cylinder two circular bases and a rounded lateral face
6. Rectangular pyramid -rectangular base and four triangular lateral faces
7. Cone- One circular base 1 rounded space that comes to a point.
8. Rectangular prism - 6 rectangular faces
I can help too yo, just post the questions and stuff like that