Help me solve this word problem ASAP (using natural logarithms)?

Question

The formula P=14.7e^(-0.21x) gives the average atmospheric pressure P in pounds per square inch , at an altitude x in miles above sea level. Find the elevation at which the average atmospheric pressure is 2 lb/in^2

"^" signifies an exponent

Answer 1

2 = 14.7 e^(-0.21x)
put natural logs on both sides: ln 2 = ln (14.7e^(-0.21x)) = ln (14.7) + ln (e^(-0.21x) = ln 14.7 -0.21x
0.21x = ln 14.7 - ln 2 = ln (14.7/2) = ln 7.35
x ~ 9.5 miles

Answer 2

ln(x - a million) + ln(x) - ln(x^2 + x - 2) = 0 combine the logs employing the residences ln(a) + ln(b) = ln(ab) ln(a) - ln(b) = ln(a/b) First, we combine the 1st 2 logs. ln[ (x - a million)x ] - ln(x^2 + x - 2) = 0 And now, we combine those 2 logs. ln [ ( x(x + a million) ) / ( x^2 + x - 2 ) ] = 0 Convert to exponential variety, e^0 = ( x(x + a million) ) / ( x^2 + x - 2 ) a million = x(x + a million) / (x^2 + x - 2) And remedy for x as prevalent. Multiply the two sides with the help of x^2 + x - 2, to get x^2 + x - 2 = x(x + a million) x^2 + x - 2 = x^2 + x x - 2 = x -2 = 0 It does not appear like there's a answer.

Answer 3

Taking the eqn for P above, we want to find x for P = 2
14.7e^(-0.21x) = 2
e^(-.021x) = 2/14.7
take natural log of both sides
-0.21x = ln2 - ln14.7
x = (ln14.7 - ln2)/0.21

Answer 4

2 = 14.7 exp { -0.21x}
2/14.7 = exp { -0.21x}
x = ln {2/14.7} / -0.21