SOLUTION: (2x - 1 )2 -4(2x -1)+ 2 =0 Not sure about my solution

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Question 180885: (2x - 1 )2 -4(2x -1)+ 2 =0
Not sure about my solution

Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
%282x+-+1+%29%5E2+-4%282x+-1%29%2B+2+=0 Start with the given equation.

Let z=2x-1 (notice there are two terms that contain 2x-1)

z%5E2+-4z%2B+2+=0 Plug in z=2x-1


Notice we have a quadratic equation in the form of az%5E2%2Bbz%2Bc where a=1, b=-4, and c=2


Let's use the quadratic formula to solve for z


z+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29 Start with the quadratic formula


z+=+%28-%28-4%29+%2B-+sqrt%28+%28-4%29%5E2-4%281%29%282%29+%29%29%2F%282%281%29%29 Plug in a=1, b=-4, and c=2


z+=+%284+%2B-+sqrt%28+%28-4%29%5E2-4%281%29%282%29+%29%29%2F%282%281%29%29 Negate -4 to get 4.


z+=+%284+%2B-+sqrt%28+16-4%281%29%282%29+%29%29%2F%282%281%29%29 Square -4 to get 16.


z+=+%284+%2B-+sqrt%28+16-8+%29%29%2F%282%281%29%29 Multiply 4%281%29%282%29 to get 8


z+=+%284+%2B-+sqrt%28+8+%29%29%2F%282%281%29%29 Subtract 8 from 16 to get 8


z+=+%284+%2B-+sqrt%28+8+%29%29%2F%282%29 Multiply 2 and 1 to get 2.


z+=+%284+%2B-+2%2Asqrt%282%29%29%2F%282%29 Simplify the square root (note: If you need help with simplifying square roots, check out this solver)


z+=+%284%29%2F%282%29+%2B-+%282%2Asqrt%282%29%29%2F%282%29 Break up the fraction.


z+=+2+%2B-+1%2Asqrt%282%29 Reduce.


z+=+2%2Bsqrt%282%29 or z+=+2-sqrt%282%29 Break up the expression.


So the answers (in terms of z) are z+=+2%2Bsqrt%282%29 or z+=+2-sqrt%282%29


However, we need the solutions in terms of "x". Remember, we let z=2x-1, so...


z+=+2%2Bsqrt%282%29 or z+=+2-sqrt%282%29 Go back to the solutions (in terms of "z")


2x-1+=+2%2Bsqrt%282%29 or 2x-1+=+2-sqrt%282%29 Plug in z=2x-1


2x+=+2%2Bsqrt%282%29%2B1 or 2x+=+2-sqrt%282%29%2B1 Add 1 to both sides (for each equation).


2x+=+3%2Bsqrt%282%29 or 2x+=+3-sqrt%282%29 Combine like terms.


x+=+%283%2Bsqrt%282%29%29%2F2 or x+=+%283-sqrt%282%29%29%2F2 Divide both sides by 2 (for each equation) to isolate "x".


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Answer:


So the solutions are x+=+%283%2Bsqrt%282%29%29%2F2 or x+=+%283-sqrt%282%29%29%2F2