Murajabash

Did I do this right? Find the vertex, the x intercepts and y intercepts. f(x)=(x-2)^2-4 Vertex: 2,4 X intercepts: 0,0 4,0 Y intercepts: I didn't know how to get these. Could you explain?

I don't know how to put this in standard form: f(x)=x^2-2x-15 I tried (x^2-2x+-x^2)-25-x^2, but x^2 doesn't factor into anything so I can't fully put it into standard form. can you show me how, plus how to find the x intercepts and y intercepts?

How come with (3,4) (vertex), and (1,2) (point) a doesn't equal -4.5, but -.5? Please show me how to get this answer.