I am totally having a brain fart ( how do you do this question ) ?
Solve for x:
log 3 81 = x
2007-06-05 06:53:19 · 6 answers · asked by monkey 2 in Science & Mathematics ➔ Mathematics
But i can only pick from..
a. 2
b. 3
c. 4
d. 0
So i guess 6 wouldn't work.
2007-06-05 07:06:04 · update #1
let y stand for x, it will make more sense.
log b (x) = y can be rewritten as b^y=x
your b is 3, your y is in unknown, and your x is 81.
plug them in to get 3^y = 81
figure out how many times 3 is multiplied by itself to get 81.
3*3*3*3 = 81
So 3^4 is 81.
The final answer is 4.
Another way to easily get the answer, assuming you have a log-functioning calculator is to divide log 81 by log 3. It's a theorem for when the base isn't 10 (the only base that calculators can use).
2007-06-05 07:09:07 · answer #1 · answered by Linduh. 3 · 0⤊ 0⤋
6
2007-06-05 06:57:33 · answer #2 · answered by rubu 2 · 0⤊ 0⤋
x=6
2007-06-05 06:57:37 · answer #3 · answered by rémy613 3 · 0⤊ 0⤋
log 3 81 = x
3^x = 81
3^x = 9^2
3^x = (3^3)^2
3^x = 3^6
x = 6
2007-06-05 06:56:56 · answer #4 · answered by Kemmy 6 · 0⤊ 0⤋
In the following, "log" means log to base 3
log 81 = x
3^x = 81
x = 4
ANSWER c
2007-06-05 07:06:07 · answer #5 · answered by Como 7 · 1⤊ 0⤋
Use the inverse (antilog) function on your calculator.
2007-06-05 06:58:47 · answer #6 · answered by Jim M 3 · 0⤊ 0⤋