Help please

A model rocket is launched from a roof into a large field. The path of the rocket can be molded by the equation y= -0.04x^2 + 8.3x + 4.3, where x is the horizontal distance, in meters, from starting point on the roof and y is the distance in the height, in meters, of the rocket above the ground.
How far horizontally from its starting point will the rocket land? Round to the nearest hundredth meter.

Question

Help please


A model rocket is launched from a roof into a large field. The path of the rocket can be molded by the equation y= -0.04x^2 + 8.3x + 4.3, where x is the horizontal distance, in meters, from starting point on the roof and y is the distance in the height, in meters, of the rocket above the ground.
How far horizontally from its starting point will the rocket land? Round to the nearest hundredth meter.

snowcrystal · Answer

A.) 208.02m
B.) 416.03m
C.) 0.52m
D.) 208.19m

random231 · Answer

hmm cool question! a medal for that at first!!!!

random231 · Answer

then the solution:

snowcrystal · Answer

sure if u can help me figure this out

random231 · Answer

okay:
suppose the rocket is launched from (0,0) in a coordinate axis.
so when it lands its y coordinate is 0.
so put y=0 in the eqn of trajectory and solve for x.
QUADRATIC EQUATION IT IS. :D

snowcrystal · Answer

so im supposed to use the quadratic equation for this?

random231 · Answer

YUP

snowcrystal · Answer

okay thanks :D i got it from here

random231 · Answer

:D