Question: why are crude oil reserve estimates somewhat unreliable.
answers:
1.all reserve estimates involve uncertainty due to the interpretation of geologic 2.some countries falsify data for political reasons.
3.the original estimates are almost low and tend to grow with time.
4.all the above.

To solve this system of equations by elimination, what operation could be used to eliminate the y-variable and find the value of x? 6x + 5y = 2 4x + 2y = 8 a) subtract 2 times the second equation from 3 times the first equation b) subtract 3 times the second equation from 2 times the first equation c) subtract 5 times the second equation from 2 times the first equation d) subtract 2 times the second equation from 5 times the first equation