SOLUTION: Please help me with this stuff I don't know much about it and I am on the verge of failing my freshman year becuase of this if you can Please help me ASAP I have a test tomarrow at

Question 82373: Please help me with this stuff I don't know much about it and I am on the verge of failing my freshman year becuase of this if you can Please help me ASAP I have a test tomarrow at 11:30 and I got a review and I have no Idea how to work it out.
for example here is a question
a golf ball is hit into the air. The path of the ball can be described by the equation h=70T-5T^2, where H is the height of the ball in meters and T is the time in second.
1. How high is the ball after 3 seconds?
2.After how many seconds will the ball be 169 meters High?
3.When will the Ball hit the ground
I need help with problems like that.My dad, Brother,Mother, and my friends donot understand it well and I asked my teacher but he said I have to figure it out on my own. but I dont even know how to do this problem so how am I supposed to figure it out if I don't even know how to do this stuff.And if I don't know how to do this stuff and don't get this review in he wont give me my test and I will fail and have to take SummerSchool or fail yet agaoin after I tryed hard and worked my butt off to try and figure it out
Please if you can help me do so I woul be much obliged if you would
Thank You, Michael F.
Answer by askmemath(368) (Show Source):
You can put this solution on YOUR website!
Given an equation in terms of Height and time
NOw the first part says how high after 3secs.
So you are given time and you have to find H. In the given equation, substitute 3 in place of T and you'll get the height
Similarly when it says how much time to reach 169m, you are given Height and you have to find T. SO replace H with 169 and solve for T
For the ball to hit the ground, H = 0 so replace H with 0 and solve for T
Please try now.