SOLUTION: Solve for x. 2x^(2/3) - 5x^(1/3) - 3 = 0 Using the Diamond Method, I got the following: 2x^(2/3) - 6x^(1/3) + x^(1/3) - 3 = 0 I then applied factoring by group.

Algebra.Com
Question 1199265: Solve for x.

2x^(2/3) - 5x^(1/3) - 3 = 0

Using the Diamond Method, I got the following:

2x^(2/3) - 6x^(1/3) + x^(1/3) - 3 = 0

I then applied factoring by group.

2x^(1/3)[x^(1/3) - 3]

Setting each factor to 0 and solving for x, I got the following

values: 0, 27

According to the textbook, x = 27 is one of the solutions.

The second value of x should be -1/8.

I did everything I could think of to find the second value of x but to no avail.

How do I find x = -1/8?


Answer by ikleyn(52790)   (Show Source): You can put this solution on YOUR website!
.
Solve for x     2x^(2/3) - 5x^(1/3) - 3 = 0
~~~~~~~~~~~~~~~~~

Prepare your equation to factoring using grouping-regrouping  (in the same way as you did in your post)

    2x^(2/3) - 6x^(1/3) + x^(1/3) - 3 = 0


Now factor left side step by step

    2x^(1/3)*(x^(1/3)-3) + (x^(1/3) - 3) = 


    (x^(1/3)-3)*(2x^(1/3)+1) = 0.


From this factored form you have EITHER first parentheses expression is zero, 
OR the second parentheses expression is zero.


(a)  Case  x^(1/3)-3 = 0.

     It gives  x^(1/3) = 3,  which implies  x = 3^3 = 27.



(b)  Case  2x^(1/3)+1 = 0.

     It gives  2x^(1/3) + 1  0,  which implies  x^(1/3) = ,  x =  = .

Solved.

The answers/(the solutions)   are   x= 27   and/or   x= ,   same as in your textbook.

Victory (!)


/////////////////


In your post, your very first step was correct, but your factoring after that was wrong.



RELATED QUESTIONS

Solve Each Equation Using The Method of Completing the Square 1.) {{{ x^2=35-2x }}} (answered by Edwin McCravy)
how would i solve these using factoring :D . 1- (x - 2)(2x - 5) = 0 2- x^2 + (answered by edjones)
Solve for x: 2x^(-2/3)- 5x^(-1/3) - 3 = 0 Any help is greatly... (answered by ewatrrr)
The questions state to simplify. Please review and help me to understand where I went... (answered by Earlsdon,scott8148,Alan3354)
Hi I have to solve the following rational inequality: 2/x+1 <= 4/x-3 The first thing I... (answered by ewatrrr,richwmiller)
Hi: I wondered if you could check this problem for me... Solve each system by the... (answered by scott8148)
i need help on these two questions (3/2)x+.5x+7=0 3/2x+11/5x=1 i need to solve... (answered by Alan3354)
3^2x - 3^x+1 +2 =... (answered by Aldorozos,robertb)
1. points are (-4,7) and (2,x) m=-1/3, find for X 2. 1/2x-3/4y=-4 1/4x+3/2y=13... (answered by lynnlo)