SOLUTION: I wasn't sure how to do this one. I got -10.5, but I don't think thats the right answer. I came to my answer by following the notes I had taken in class. I'm just really unsure abo

Algebra ->  Conversion and Units of Measurement -> SOLUTION: I wasn't sure how to do this one. I got -10.5, but I don't think thats the right answer. I came to my answer by following the notes I had taken in class. I'm just really unsure abo      Log On


   

Question 72214: I wasn't sure how to do this one. I got -10.5, but I don't think thats the right answer. I came to my answer by following the notes I had taken in class. I'm just really unsure about this problem. Thanks for any help. :]
+%284.2%2A10%5E%287%2B2n%29%29%2F%282.1%2A10%5E%28-8%29%29=0.000002+
Found 2 solutions by rmromero, stanbon:
Answer by rmromero(383) About Me  (Show Source):
You can put this solution on YOUR website!


+%284.2%2A10%5E%287%2B2n%29%29%2F%282.1%2A10%5E%28-8%29%29=0.000002+



Rewrite 0.000002  in scientific notation



       2+%2A+10%5E-6



Rewrite the whole equation again



+%284.2%2A10%5E%287%2B2n%29%29%2F%282.1%2A10%5E%28-8%29%29=+2%2A10%5E%28-6%29



simplify the left side of the equation by dividing.



     4.2%2F2.1+%2810%5E7+%2B+2n+%2B+8%29+=+2%2A10%5E%28-6%29



              +2%2A+10%5E%282n%2B15%29+=+2%2A10%5E%28-6%29



Since bases are the same,

          2n + 15 = -6

          2n = -6 - 15

          2n = -21

           n = -21/2 or -10.5

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
(4.2*10^(7+2n))/(2.1*10^(-8))=0.000002
You are correct: n= -10.5
Cheers,
Stan H.