can someone explain how to do this?
2007-01-21 16:15:13 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
81^3/4 = (3^4)^(3/4) = 3^[4*(3/4)] = 3^3 = 27
2007-01-21 16:19:17 · answer #1 · answered by Phineas Bogg 6 · 1⤊ 0⤋
You could just plug it into your calculator, but that is for the lazy.
81^(3/4)=(81^(1/4))^3=3^3=27
2007-01-22 01:14:19 · answer #2 · answered by yupchagee 7 · 0⤊ 0⤋
81^(3/4) means that one has to take the fourth root of 81 then raise that number to the 3rd power. So,
81^(3/4)=
3^3=27
I hope that this helps.
2007-01-22 00:20:54 · answer #3 · answered by unhrdof 3 · 0⤊ 0⤋
81 = 3^4.
so this 4 cancels with 4 of 3/4, leaving you with 3^3
ans = 3^3 = 27
2007-01-22 00:38:16 · answer #4 · answered by frolicchap 1 · 0⤊ 0⤋
81^¾ = 4â81³
to write it in scientific language!
2007-01-22 00:25:47 · answer #5 · answered by Benedict W 1 · 0⤊ 0⤋
81^3/4 = ((81^1/4))^3 = 9^3 =729
2007-01-22 08:27:45 · answer #6 · answered by santmann2002 7 · 0⤊ 0⤋
If you have a graphing calculator, enter 81. Then you will see (to the upper right) a little button that looks like an upward carat (^). Press this, then simply enter 3 divided by 4. Make sure this is all in one line. Then press enter. Your result should be 27. Was that helpful? =]
2007-01-22 00:24:53 · answer #7 · answered by mr_4dman 1 · 0⤊ 0⤋
81^(3/4)
is the same as saying
The quadratic root of 81 and then cubing that answer (^3)
Quad root of 81 = 3
3^3
= 27
It's just another way of looking at roots.
2007-01-22 00:20:29 · answer #8 · answered by Kipper to the CUP! 6 · 0⤊ 0⤋
Absolutely.
For fractional exponents a^(m/n), it means, in words,
"take the n-th root of a to the power of m"
In our case, it's
"Take the fourth root of 81 cubed."
You can do the cubing before or after calculating the 4th root. That is,
(81^(1/4))^3
The fourth root of 81 is 3, so we have
3^3
which is equal to
27
2007-01-22 00:19:46 · answer #9 · answered by Puggy 7 · 1⤊ 0⤋