SOLUTION: ).1x^2-0.2x-0.9=0 the directions say: solve the equation by completing the square

Algebra ->  Square-cubic-other-roots -> SOLUTION: ).1x^2-0.2x-0.9=0 the directions say: solve the equation by completing the square      Log On


   

Question 690214: ).1x^2-0.2x-0.9=0
the directions say: solve the equation by completing the square
Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
Divide the entire equation by .1
x%5E2+-+2x+-+9+=+0
Move the 9 to the other side
x%5E2+-+2x+=+9
Take 1%2F2 of the x coefficient and square it: %28%281%2F2%29b%29%5E2
...
b came from ax%5E2%2Bbx%2Bc=0
...
%281%2F2%292+=+1%5E2+=+1
Add 1 to both sides
x%5E2+-+2x+%2B+1+=+9+%2B+1
%28x-1%29%5E2+=+10
...
sqrt%28x-1%29%5E2 = +/- sqrt%2810%29
x-1 = +/-sqrt%2810%29
...
x=1%2B-sqrt%2810%29
...
highlight_green%28x=1%2Bsqrt%2810%29%29 and highlight_green%28x=1-sqrt%2810%29%29