SOLUTION: D=(n^2-3n) / 2 Solve for n Also the drop down box seems to be not working properly so I am unsure what I am choosing for a topic.

Algebra ->  Expressions-with-variables -> SOLUTION: D=(n^2-3n) / 2 Solve for n Also the drop down box seems to be not working properly so I am unsure what I am choosing for a topic.      Log On


   

Question 600301: D=(n^2-3n) / 2

Solve for n
Also the drop down box seems to be not working properly so I am unsure what I am choosing for a topic.
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
D=%28n%5E2-3n%29%2F2


2D=n%5E2-3n


0=n%5E2-3n-2D


n%5E2-3n-2D=0


Now use the quadratic formula to solve for 'n'. In this case, A=1, B+=+-3 and C=-2D


n+=+%28-B+%2B-+sqrt%28+B%5E2-4AC+%29%29%2F%282A%29


n+=+%28-%28-3%29+%2B-+sqrt%28+%28-3%29%5E2-4%281%29%28-2D%29+%29%29%2F%282%281%29%29


n+=+%283+%2B-+sqrt%28+9+%2B+8D+%29%29%2F%282%29


n+=+%283+%2B+sqrt%28+9+%2B+8D+%29%29%2F%282%29 or n+=+%283+-+sqrt%28+9+%2B+8D+%29%29%2F%282%29


So the solutions are n+=+%283+%2B+sqrt%28+9+%2B+8D+%29%29%2F%282%29 or n+=+%283+-+sqrt%28+9+%2B+8D+%29%29%2F%282%29