SOLUTION: I have a problem that when I solve it, it seems something is going wrong and I am getting a strange solution. The problem is 0=-16T^2+5T+15 I know that a=-16 and b=5 and c=15 w

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: I have a problem that when I solve it, it seems something is going wrong and I am getting a strange solution. The problem is 0=-16T^2+5T+15 I know that a=-16 and b=5 and c=15 w      Log On


   

Question 195150This question is from textbook
: I have a problem that when I solve it, it seems something is going wrong and I am getting a strange solution. The problem is 0=-16T^2+5T+15 I know that a=-16 and b=5 and c=15 we have to use the quadratic formula x=-b+sqrtb^2-4ac
Please help me!!!! thank you soo much This question is from textbook

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

0=-16t%5E2%2B5t%2B15 Start with the given equation.


Notice we have a quadratic equation in the form of 0=at%5E2%2Bbt%2Bc where a=-16, b=5, and c=15


Let's use the quadratic formula to solve for t


t+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


t+=+%28-%285%29+%2B-+sqrt%28+%285%29%5E2-4%28-16%29%2815%29+%29%29%2F%282%28-16%29%29 Plug in a=-16, b=5, and c=15


t+=+%28-5+%2B-+sqrt%28+25-4%28-16%29%2815%29+%29%29%2F%282%28-16%29%29 Square 5 to get 25.


t+=+%28-5+%2B-+sqrt%28+25--960+%29%29%2F%282%28-16%29%29 Multiply 4%28-16%29%2815%29 to get -960


t+=+%28-5+%2B-+sqrt%28+25%2B960+%29%29%2F%282%28-16%29%29 Rewrite sqrt%2825--960%29 as sqrt%2825%2B960%29


t+=+%28-5+%2B-+sqrt%28+985+%29%29%2F%282%28-16%29%29 Add 25 to 960 to get 985


t+=+%28-5+%2B-+sqrt%28+985+%29%29%2F%28-32%29 Multiply 2 and -16 to get -32.


t+=+%28-5%2Bsqrt%28985%29%29%2F%28-32%29 or t+=+%28-5-sqrt%28985%29%29%2F%28-32%29 Break up the expression.


t+=+%285-sqrt%28985%29%29%2F%2832%29 or t+=+%285%2Bsqrt%28985%29%29%2F%2832%29 Reduce


So the answers are t+=+%285-sqrt%28985%29%29%2F%2832%29 or t+=+%285%2Bsqrt%28985%29%29%2F%2832%29


which approximate to t=-0.825 or t=1.137