81=x^4

Question

81=x^4

zzr0ck3r · Answer

you need a number a such that a*a*a*a = 81

zzr0ck3r · Answer

what is the first number you would try?

anonymous · Answer

is there no other method apart from trial n error

zzr0ck3r · Answer

sure there is
x^4 = 81
(x^2)^2 = 81 = 9^2
so x^2 = 9
what is x?

anonymous · Answer

3

anonymous · Answer

wat abt 256=x^4

anonymous · Answer

Can you post to the correct section please? Just do 4th root on your calculator.

zzr0ck3r · Answer

what is the square root of 256?

zzr0ck3r · Answer

also the answer to the other problem is {3,-3}

zzr0ck3r · Answer

x^4 = 256 = 16^2
so (x^2)^2 = 16^2 
so x^2 = 16
what is x?

tkhunny · Answer

Or, if you want to find ALL the solutions, you may wish to solve using normal COMPELTE methods.

$x^{4} = 81$

$x^{4}  - 81 = 0$

$(x^{2} - 9)(x^{2} + 9) = 0$

$(x - 3)(x+3)(x^{2} + 9) = 0$

And the two Real solutions are pretty clear.

zzr0ck3r · Answer

Ah I figured we are dealing with R

anonymous · Answer

ok I getn it guys

triciaal · Answer

another alternative would be to use logs
4log x = log 81
log x = log 81 /(4) = 1.908/4 = 0.477
x = 10^.477 = 2.999  therefore use 3

tkhunny · Answer

All these ideas are lovely, unless you want ALL the solutions.  FACTOR!