# Thread: Solve equation

1. ## Solve equation

I cannot figure out how to get to the solution of 12/5 for the equation:

2x(4-x)^-1/2 - cube root(4-x)= 0

Sorry, I do not know how to write the cube root.

I tried to write the equation in different ways by using the laws
x^-1/2 = 1/x^1/2

or

cube root(x) = x^1/3

but that does not help me.

Any idea that would help me to get in the right direction?
Thanks

2. Originally Posted by DBA
I cannot figure out how to get to the solution of 12/5 for the equation:

2x(4-x)^-1/2 - cube root(4-x)= 0

Sorry, I do not know how to write the cube root.

I tried to write the equation in different ways by using the laws
x^-1/2 = 1/x^1/2

or

cube root(x) = x^1/3

but that does not help me.

Any idea that would help me to get in the right direction?
Thanks
Could that be because 12/5 is not a solution of that equation? The actual root apprars to be close to 1.2.

CB

3. Thank you for the hint. I did not plug in the solution. I need to check the exercise again, seems not to be right.
Next time I stuck, I will see if the solution is a part of the equation at all.

4. , by successive approximation, we have x = 1.185

Look at the graph,