3^x = 1/81.
What is x?
2007-03-29 07:48:43 · 7 answers · asked by phuphubeanz 1 in Science & Mathematics ➔ Mathematics
x log3 = log(1/81)
x = log(1/81)/log3 = -4
2007-03-29 07:57:33 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Since 1/81 is 1/3^-4 then 3^x is -4
2007-03-29 08:05:21 · answer #2 · answered by eliannemsr 2 · 0⤊ 0⤋
x = 4
2007-03-29 09:08:11 · answer #3 · answered by angel 2 · 0⤊ 0⤋
3^4=81
3^-4=1/81
2007-03-29 08:05:32 · answer #4 · answered by Dave aka Spider Monkey 7 · 0⤊ 0⤋
Take the natural log of both sides:
ln[3^x] = ln[1/(9^2)] = ln[9^(-2)]
x ln[3] = -2 ln[9] = -2 ln[3^2] = -2(2) ln[3]
x = -4 ln[3]/ln[3] = -4
2007-03-29 07:56:22 · answer #5 · answered by kellenraid 6 · 0⤊ 0⤋
3^x=3^-4
x=-4
2007-03-29 07:52:27 · answer #6 · answered by azimef 2 · 0⤊ 0⤋
first i need to know what A is?
2007-03-29 08:27:34 · answer #7 · answered by Anonymous · 0⤊ 0⤋