acceleration motion problem.

I got most of them this weekend. There's just a few I'm not sure about.

1. NASA launches a rocket at http://hosted.webwork.rochester.edu/...388a5f95d1.pngseconds. Its height, in meters above sea-level, as a function of time is given by http://hosted.webwork.rochester.edu/...34bda8d651.png.

Assuming that the rocket will splash down into the ocean, at what time does splashdown occur?

The rocket splashes down after ______ seconds.

How high above sea-level does the rocket get at its peak?

The rocket peaks at _______ meters above sea-level.

2.Solve the equation http://hosted.webwork.rochester.edu/...b0c587f2f1.png by factoring.

I know that one of the solutions is definitly -8. The other one I'm getting 5/4 but it says that's wrong.

3.Complete the equation of the circle centered at (-1,-1) with radius 6.

I'm getting 34=0 for this but I'm not to sure what the equation for a cirlce is.

4.A vendor sells ice cream from a cart on the boardwalk. He offers vanilla, chocolate, strawberry, blueberry, and pistachio ice cream, served on either a waffle, sugar, or plain cone. How many different single-scoop ice-cream cones can you buy from this vendor?

Do I use nPr or nCr for this one? And which number equals n and which one equals r.

5. The angle of elevation to the top of a building is found to be 13 degrees from the ground at a distance of 4500 feet from the base of the building. Find the height of the building.

I got 2 answers for this. 385205.8259 or 1038.90686