<span>B. {-5,-4,-3…. }
............</span>
Answer:
The rocket hits the ground at a time of 11.59 seconds.
Step-by-step explanation:
The height of the rocket, after x seconds, is given by the following equation:
It hits the ground when , so we have to find x for which , which is a quadratic equation.
Finding the roots of a quadratic equation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots such that , given by the following formulas:
In this question:
So
Since time is a positive measure, the rocket hits the ground at a time of 11.59 seconds.
7*y - 5*(4-2y) = 7y - 20 +10y = 17y-20 = 31,
y =3, x = -2.
Weird 20 min without answer!