math
posted by Jane .
Landon is standing in a hole that is 6.7 ft deep. He throws a rock and it goes up into the air, out of the hole, and then lands on the ground above. the path of the rock can be modeled by the equation
y= 0.005x^2 + 0.48x  6.7, where x is the horizontal distance of the rock, in meters, from Landon and y is the height, in meters, of the rock above the ground. How far horizontally from Landon will the rock land?
I got two answers: 17 and 79; however, I do not know which is x or y, nor horizontal. Please help!

y is vertical, x is horzontal. When the rock is at y=0, you need to find x.
0=.005x^2+.48x6.7
0=x^296x+1340
so x comes out 17, and 79 (rounded)
So there are two answers, and in the real world, he could have thrown it with two different velocities. Remember these problems are "contrived", and may not match the real world we live in. 
There are two answers to chose from:
A: 16.95
B: 79.05
Which is horizontal?