更新1:
after that i put x^3-64=0, after: (x-4)(x^2+4x+16)=0. what should i do after these? and i also know that x=4, but its not the only answer.
what is the value of x? x^3=64?
2008-12-13 3:01 pm
after that i put x^3-64=0, after: (x-4)(x^2+4x+16)=0. what should i do after these?
回答 (9)
2008-12-13 3:22 pm
✔ 最佳答案
x³ - 64 = 0(x - 4)(x² + 4x + 16) = 0
(x - 4) = 0
x = 4
(x² + 4x + 16) = 0
x = {-4 ± √[4² - 4(1)(16)]}/2(1)
x = (-4 ± √-48)/2
x = (-4 ± 4√-3)/2
x = -2 ± 2√-3
x = -2 ± 2i√3
So x = 4, -2 - 2i√3, -2 + 2i√3
2008-12-13 3:12 pm
The answers above me are right, the solution is quite clearly 4, hoever, if you INSIST on doing it by taking a factor out:
(x-4)(x^2+4x+16)=0
therefore, one of the two must =0:
x-4=0
x=4
the other one gives you:
x^2 +4x +16=0
Which has no (real) solution, therefore the only value for f(x)=0 is the one we just found above:
x=4
(x-4)(x^2+4x+16)=0
therefore, one of the two must =0:
x-4=0
x=4
the other one gives you:
x^2 +4x +16=0
Which has no (real) solution, therefore the only value for f(x)=0 is the one we just found above:
x=4
2008-12-13 3:48 pm
x³ - 64 = 0
(x - 4)(x² + 4x + 16) = 0
(x - 4) = 0
x = 4
(x² + 4x + 16) = 0
x = {-4 ± â[4² - 4(1)(16)]}/[2(1)]
x = (-4 ± â-48)/2
x = (-4 ± 4â-3)/2
x = -2 ± 2â-3
x = -2 ± 2iâ3
Possible values for x are:
x = 4, -2-2iâ3, -2 + 2iâ3
(x - 4)(x² + 4x + 16) = 0
(x - 4) = 0
x = 4
(x² + 4x + 16) = 0
x = {-4 ± â[4² - 4(1)(16)]}/[2(1)]
x = (-4 ± â-48)/2
x = (-4 ± 4â-3)/2
x = -2 ± 2â-3
x = -2 ± 2iâ3
Possible values for x are:
x = 4, -2-2iâ3, -2 + 2iâ3
參考: College student
2008-12-13 3:16 pm
Well, there is an easy way to find the value of x on x^3=64.
Its simple, just get the cube root of 64 answer we get is x=4
x^3=64
x=sqrt[3]{64}
x=4
to check your answer, just plug in x=4 to x^3=64
4^3=64
64=64 correct..
Its simple, just get the cube root of 64 answer we get is x=4
x^3=64
x=sqrt[3]{64}
x=4
to check your answer, just plug in x=4 to x^3=64
4^3=64
64=64 correct..
2008-12-13 3:16 pm
x^3=64
Substitute x=4 ,equation satisfies
x*x*x=64
U can factorise 64 as 2*2*2*2*2*2=4*4*4
Here, x=4
Substitute x=4 ,equation satisfies
x*x*x=64
U can factorise 64 as 2*2*2*2*2*2=4*4*4
Here, x=4
2008-12-13 3:10 pm
(x-4) = 0
x=4
(x^2+4x+16)=0
(x+4)(x+4)=0
x= -4
4^3 = 64
(-4)^3 = -64
therefore x=4
x=4
(x^2+4x+16)=0
(x+4)(x+4)=0
x= -4
4^3 = 64
(-4)^3 = -64
therefore x=4
2008-12-13 3:09 pm
x^3 = 64
x = ³â64
x = ³â(4 * 4 * 4)
x = 4
x = ³â64
x = ³â(4 * 4 * 4)
x = 4
2008-12-13 3:08 pm
wrte down the answer to the question, in case you arent smart enough
x=4 so 4^3=64
x=4 so 4^3=64
2008-12-13 3:06 pm
By inspection , x = 4
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