the four is actually the fourth root of x and the x before the four is multiplication sign.
2006-09-07 17:19:46 · 7 answers · asked by naya w 2 in Science & Mathematics ➔ Mathematics
If I understand your problem correctly, the question basically is:
sqrt(x-7) * x^(1/4) = 8
First, square both sides:
[ sqrt(x-7) * x^(1/4) ]^2 = 8^2
==> (x-7) * sqrt(x) = 64
Square both sides again:
[ (x-7) * sqrt(x) ]^2 = 64^2
==> (x-7)^2 * (x) = 4096
So basically you have:
==> x (x-7) (x-7) = 4096 ==> x^3 -14x^2 + 49x = 4096
==> x^3 -14x^2 + 49x - 4096 = 0
Solve using synthetic division or matlab software to give:
x = 9.584, 2.2079+1.343 i, 2.2079-1.343 i
Hope this helps.
2006-09-07 18:20:54 · answer #1 · answered by Esmeralda 2 · 0⤊ 0⤋
[x^(1/2)-7] . x^(1/4)=8
(t^2-7).t=8 if x^(1/4)=t
t^3-7t-8=0
This is cubic equation. Find t then find the fourth power of it .
it will be the value of x.
2006-09-08 00:29:37 · answer #2 · answered by iyiogrenci 6 · 0⤊ 0⤋
North Dakota?
2006-09-08 00:25:12 · answer #3 · answered by Evel Man 3 · 0⤊ 0⤋
xtine has as good an answer as any âº
Doug
2006-09-08 00:23:05 · answer #4 · answered by doug_donaghue 7 · 0⤊ 1⤋
problem not clear
2006-09-08 00:29:48 · answer #5 · answered by raj 7 · 0⤊ 0⤋
i could not read it. can you express it using "sqrt"?
2006-09-08 00:24:30 · answer #6 · answered by sunsunnysuntinna 1 · 0⤊ 0⤋
go to math.com
2006-09-08 00:21:40 · answer #7 · answered by ??? 2 · 0⤊ 1⤋