Simple Maths Problem

frozen7

Simple Maths Problem....:)

How to solve this equation?
( 3 ((x+1)^1/2))^1/2 = (3x-5)^1/2

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geosonel

frozen7 said:
How to solve this equation?
( 3 ((x+1)^1/2))^1/2 = (3x-5)^1/2
first, square both sides
then, square both sides again

Last edited:

frozen7

I cant find the correct answer in this way...the answer should be (13+(105)^1/2)/6 actually...

geosonel

frozen7 said:
I cant find the correct answer in this way...the answer should be (13+(105)^1/2)/6 actually...
you'll get that answer (plus 1 other that must be discarded).
show your work if you still have trouble

frozen7

Can you please show me the work? I still cant find it....thanks...

Knavish

I'm not sure what you're not getting... Square both of the sides twice, and come up with the quadratic 9x^2-39x+16. The solution for this will of course contain two answers, but one will be invalid.

frozen7

ya...i get this final equation...but i get the value of x= (13 +/- (233)^1/2) / 6

geosonel

frozen7 said:
How to solve this equation?
( 3 ((x+1)^1/2))^1/2 = (3x-5)^1/2
square first time:
3 ((x+1)^1/2) = (3x-5)
square second time:
9(x+1) = 9x^2 - 30x + 25
rearrange:
9x^2 - 39x + 16 = 0
x = (1/18)*(39 ± (1521 - 576)^(1/2))
x = (1/18)*(39 ± (945)^(1/2))
divide num & denom by 3:
x = (13 ± (105)^1/2)/6
x = 3.8745 or 0.4588
check answers in problem eq:
0.4588 - no good (discard)
3.8745 - ok

frozen7

oh..thanks...just meet some mistakes...

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