Solve the problem. Give the answer to the nearest tenth.
-The position of an object moving in a straight line is given by $s = 2 t ^ { 2 } - 3 t$, where s is in meters and $t$ is the time in seconds the object has been in motion. How long (to the nearest tenth) will it take the object to move 9 meters?
A) $3.0 \mathrm { sec }$
B) $13.5 \mathrm { sec }$
C) $10.0 \mathrm { sec }$
D) $2.8 \mathrm { sec }$

Question

Quizplus · Accepted Answer

To find the time it takes the object to move 9 meters, we need to solve the equation $2 t ^ { 2 } - 3 t = 9$. Factoring the left side of the equation, we get $(2 t - 3) (t - 3) = 9$. Setting each factor equal to zero, we get $2 t - 3 = 0$ and $t - 3 = 0$. Solving each equation, we get $t = 1.5$ and $t = 3$. Since the object cannot move backwards, we discard the negative solution. Therefore, it will take the object 3 seconds to move 9 meters.

Solve the Problem s=2t2−3ts = 2 t ^ { 2 } - 3 ts=2t2−3t

Solve the Problem $s = 2 t ^ { 2 } - 3 t$