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please help, stumped with this one!!!

2007-01-19 03:14:49 · 9 answers · asked by leah_bored 1 in Science & Mathematics Mathematics

9 answers

x^2 = 4 x

solution 1, x = 0
then x = 4, so we have


solution 2, x = 4.

2007-01-19 03:20:47 · answer #1 · answered by Jano 5 · 1 0

x= 0 ,4

2007-01-19 03:20:49 · answer #2 · answered by rajeev_iit2 3 · 0 0

x - 2sqrt(x) = 0
Add 2 sqrt(x) to both sides
x = 2 sqrt(x)
Squaring both sides
x*2 = 4x
Subtracting 4x from both sides and factorizing
x . (x - 4) = 0
Hence, x = 0 and (x - 4) = 0
x = 0 and x = 4

Note: please check by plugging if the values of x are valid. When you square both sides, there is a possibility that an extraneous value may come out which will not satisfy the equation. Here both values are valid.

2007-01-19 03:26:33 · answer #3 · answered by Sheen 4 · 0 0

The answer is 0, 4.

Now, how did they do that?

x - 2x^(1/2) = 0, multiply both sides of the equation by (x + 2x^(1/2))

(x-2x^(1/2)) (x+2x^(1/2)) = 0 (x-2x^(1/2))

x^2 - 4x = 0, now factor out the x

x(x-4) = 0

x = 0, x = 4

Check the work by plugging the answers back in...hope this helps

2007-01-19 03:25:45 · answer #4 · answered by Rockit 5 · 0 0

you can write x=2sqrt x (Consider xmust be >=0) Squaring both sides x^2=4x ==> x(x-4)=0 so x=0 ,x=4

2007-01-19 05:26:36 · answer #5 · answered by santmann2002 7 · 0 0

Factor in terms of sqrtx:
sqrtx(sqrtx-2) = 0
→ sqrtx = 0 or sqrtx = 2
→ x=0 or x=4.

2007-01-19 03:53:39 · answer #6 · answered by Anonymous · 0 0

x - 2 sqrt(x) = 0

x = 2 sqrt(x)

x/2 = sqrt(x) ... Now sqaure both sides:

(x/2) * (x/2) = x

(1/4) x² = x ... Now rearrange terms

(1/4) x² - x = 0 ... Solve this quadratic.
... First kill the Fraction (mult. by 4)

x² - 4x = 0 ... Complete the Square

2007-01-19 03:42:12 · answer #7 · answered by Razor 2 · 0 0

you write x-2sqrt x =0

x=2sqrt x

square this

x^2 = 4x ---> x(x-4) =0

roots x=0 x=4

It works !

2007-01-19 03:23:42 · answer #8 · answered by maussy 7 · 0 0

put the entire equation to the second power, then you have:
x-squared - 4x = 0, which should be easier to solve.

2007-01-19 03:21:47 · answer #9 · answered by AH 3 · 0 1

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