Analytic Geometry Answers

If the tangents at two points of a parabola are at right angles, then show that they intersects at a point on the directrix.

Question 1100429: Which of the following equations represents an ellipse having a major axis of length 18 and foci located at 4,7) and 4,11)? (There's supposed to be a parenthesis there I can't put it something pops up.) I'm doing all this on my computer there really hasent been any examples on how to do these and there's no teacher lecturing all this which is why I need help with all these.
A.(x-9)^2/81+(y-4)^2/4=1
B.(x-4)^2/77+(y-9)^2/81=1
C.(x-9)^2/77+(y-4)^2/81=1
D.(x-4)^2/81+(y-9)^2/77=1
I don't think it's D or A

A software designer is mapping the streets for a new racing game. All of the streets are depicted as either perpendicular or parallel lines. The equation of the lane passing through A and B is -7x + 3y = -21.5. What is the equation of the central street PQ?

An archeologist found the remains of an ancient spartans’s shield, which she then placed on a grid. If an arc of the shield passes through A(−6,0), B(2,4) and C(6,0), locate the center of the shield, and the standard equation defining its boundary.

The earth revolves around the sun along an ellipse. The sun lies in the focus of the ellipse. The largest distance from the sun to the earth is 152.1 million kilometers, and the shortest is 147.1 million kilometers. Find the length of the semi minor axis of the ellipse and the eccentricity of the ellipse. What is the distance between the two foci of the ellipse?

the coordinates of point P and Q are (-2,3) and (1,2) respectively .A straight line QR is perpendicular ti the straight line PQ.find the equation of the straight line QR

given two points P(2,1) and Q(4,7).find an equation of the straight line passing through Q and perpendicular to PQ

Find the sections of the conicoid
x^2/36 + y^2/9 - z^2/4 = x^2-1 by the coordinate and identify them.

The equation x^2+y^2-2xy+2x++1=0 represents a parabola