SOLUTION: can someone help me please???? In testing a certain machined part, it is found that the number of failures, F, increases with hours of use, h, according to the equation F=8.69*l

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: can someone help me please???? In testing a certain machined part, it is found that the number of failures, F, increases with hours of use, h, according to the equation F=8.69*l      Log On


   

Question 768188: can someone help me please????
In testing a certain machined part, it is found that the number of failures, F, increases with hours of use, h, according to the equation F=8.69*ln[h] + 20. Find the number of hours of use which leads to 75 failures.
Hours of use (nearest integer):
Answer by josgarithmetic(39621) About Me  (Show Source):
You can put this solution on YOUR website!
F=8.69%2Aln%28h%29+%2B+20


Want h when F is known.
F-20=8.69%2Aln%28h%29
ln%28h%29=%28F-20%29%2F8.69

highlight%28h=e%5E%28%28F-20%29%2F8.69%29%29
Now assign 75 to F. Compute h.

In case the code tagging and highlighting interfere, that formula is
h=e^((F-20)/8.69)