Answer:

Step-by-step explanation:
You add the like-terms so the things that are the same, pretty much.
so 3t^2+7t^2 = 10t^2
and you can subtract 8t^2 from 10t^2 because they are like terms so you get 2t^2
then bring -5t down and subtract 9 from 6 and boom you're done
Answer: YZ = 13
Point Y is between the points X and Z => XY + YZ = XZ
=> 3x - 4 + 2x + 3 = 24
<=> 5x - 1 = 24
<=> x = (24 + 1) : 5 = 5
with x = 5 => YZ = 2.5 + 3 = 13
Step-by-step explanation:
Just divide -30 m/s (the change in velocity) by 12 seconds (the time required for the car to come to a stop):
-30 m/s
----------- = - 2,5 m / (sec)^2 (answer)
12 sec