SOLUTION: Solve the equation for x. Round your answer to two decimal places, and do not include 'x' in answer? 6*4^x=99

Algebra ->  Exponential-and-logarithmic-functions -> SOLUTION: Solve the equation for x. Round your answer to two decimal places, and do not include 'x' in answer? 6*4^x=99      Log On


   



Question 604786: Solve the equation for x. Round your answer to two decimal places, and do not include 'x' in answer?
6*4^x=99

Answer by bucky(2189) About Me  (Show Source):
You can put this solution on YOUR website!
given to solve for x:
.
6%2A4%5Ex=99
.
First, take the base 10 log of both sides:
.
log%286%2A4%5Ex%29+=+log%2899%29
.
Using the product rule for logarithms, split the left side into two logarithms:
.
log%286%29+%2B+log%284%5Ex%29+=+log%2899%29
.
Subtract log(6) from both sides to get:
.
log+%284%5Ex%29+=+log%2899%29+-+log%286%29
.
By the rules for logarithms, an exponent can be brought outside as a multiplier. Therefore, on the left side, bring the x out as a multiplier of the logarithm. The result is:
.
x%2Alog%284%29+=+log%2899%29+-+log%286%29
.
Divide both sides by log(4):
.
x+=+%28log%2899%29+-+log%286%29%29%2Flog%284%29
.
Use a calculator to find that log(99) = 1.995635195, log(6) = 0.77815125, and log(4) = 0.602059991. Substitute these values into the equation for x to get:
.
x+=+%281.995635195+-+0.77815125%29%2F0.602059991
.
Subtract the two terms on the numerator:
.
x+=+1.217483945%2F0.602059991
.
Do the division on the right side and you have:
.
x+=+2.022197062
.
The problem tells you to round this answer to two decimal places. When you do that, the answer shortens to:
.
x+=+2.02
.
That's the answer that you're looking for. Hope this helps you to understand the process and the rules that apply to logarithms better.
.