Focus is at (2,5) and the directrix is y = -7. Find the equation of the parabola.

In triangle abc segment de is parallel to the side ac . (the endpoints of segment de lie on the sides ab and bc respectively). find de, if ac=20cm, ab=17cm, and bd=11.9cm;

Aline on the wall and a line on the floor are skew. always, sometimes, or never?

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)