+318 Consider the following.
21 − x = 9
(a) Find the exact solution of the exponential equation in terms of logarithms.
(b) Use a calculator to find an approximation to the solution rounded to six decimal places.
x =
+128408 21 - x = 9 is not an exponential equation
I think this might be
2^(1 - x) = 9 ???
Take the log of both sides
log 2 ^(1 - x) = log 9 and we can write
(1 - x) log 2 = log 9 divide both sides by log 2
1 - x = log 9 / log 2 rearrange as
x = 1 - log 9 / log 2
This is the exact answer in log terms
Evaluating with a calculator we get ≈ -2.169925
