SOLUTION: solve by completing square 4 x^2 - 8x - 2 = 0

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Question 209416: solve by completing square 4 x^2 - 8x - 2 = 0
Found 2 solutions by Earlsdon, RAY100:
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
SOLVE BY COMPLETING THE SQUARE:
4x%5E2-8x-2+=+0 First, divide both sides by 4 so as to get the x%5E2 coefficient equal to 1.
x%5E2-2x-1%2F2+=+0 Now add 1%2F2 to both sides.
x%5E2-2x+=+1%2F2 Complete the square in x by adding the square of half the x-coefficient to both sides, that's %28-2%2F2%29%5E2+=+1:
x%5E2-2x%2B1+=+%281%2F2%29%2B1 Simplify.
%28x-1%29%5E2+=+3%2F2 Take the square root of both sides.
x-1+=+sqrt%283%2F2%29 or x-1+=+-sqrt%283%2F2%29 Finally, add 1 to both sides of each solution.
highlight%28x+=+1%2Bsqrt%283%2F2%29%29 or highlight%28x+=+1-sqrt%283%2F2%29%29

Answer by RAY100(1637) About Me  (Show Source):
You can put this solution on YOUR website!
4x^2 -8x -2 =0
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divide by 4 to get leading coefficient =1
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x^2 -2x -1/2 =0
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move constant to rt side
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x^2 -2x = 1/2
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take coefficient of 2nd term,,,divide by 2,, and square
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(2/2)^2 =1,,,,,add to both sides of eqn
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x^2 -2x +1 = 1/2 +1
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(x-1)^2 = 1.5
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take square root of both sides
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x-1 = +/- 1.225
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x=+1.225 +1 = 2.225,,,,,or x= -1.225 +1 = -.225
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check(2.225),,,4(2.225)^2 -8(2.225)-2 = 0,,,,,ok
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(-.225),,,,4(-.225)^2 -8(-.225) -2 = 0,,,,,,ok
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