SOLUTION: Please solve this problem ASAP. I have a test tomorrow and I am doing extra practice to prepare. I completed this problem, but I am unsure if I did it correctly. Thanks in advance

Algebra ->  Square-cubic-other-roots -> SOLUTION: Please solve this problem ASAP. I have a test tomorrow and I am doing extra practice to prepare. I completed this problem, but I am unsure if I did it correctly. Thanks in advance       Log On


   

Question 746927: Please solve this problem ASAP. I have a test tomorrow and I am doing extra practice to prepare. I completed this problem, but I am unsure if I did it correctly. Thanks in advance for helping me. Complete the square of the following problem: 2x^2 - 4x - 3 = 0
I got the answer: x = 1 +/- sqrt5/2
*+/- = positive negative
*sqrt = square root
Thanks again in advance.
Found 2 solutions by jim_thompson5910, josmiceli:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
2x%5E2+-+4x+-+3+=+0

2x%5E2+-+4x+=+3

2%28x%5E2+-+2x%29+=+3

2%28x%5E2+-+2x%2B1-1%29+=+3

2%28%28x%5E2+-+2x%2B1%29-1%29+=+3

2%28%28x-1%29%5E2-1%29+=+3

2%28x-1%29%5E2-2+=+3

2%28x-1%29%5E2+=+3%2B2

2%28x-1%29%5E2+=+5

%28x-1%29%5E2+=+5%2F2

x-1+=+sqrt%285%2F2%29 or x-1+=+-sqrt%285%2F2%29

x-1+=+sqrt%285%29%2Fsqrt%282%29 or x-1+=+-sqrt%285%29%2Fsqrt%282%29

x-1+=+%28sqrt%285%29sqrt%282%29%29%2F%28sqrt%282%29sqrt%282%29%29 or x-1+=+-%28sqrt%285%29sqrt%282%29%29%2F%28sqrt%282%29sqrt%282%29%29

x-1+=+%28sqrt%2810%29%29%2F%28sqrt%284%29%29 or x-1+=+-%28sqrt%2810%29%29%2F%28sqrt%284%29%29

x-1+=+%28sqrt%2810%29%29%2F%282%29 or x-1+=+-%28sqrt%2810%29%29%2F%282%29

x+=+1%2B%28sqrt%2810%29%29%2F%282%29 or x+=+1-%28sqrt%2810%29%29%2F%282%29

x+=+2%2F2%2B%28sqrt%2810%29%29%2F%282%29 or x+=+2%2F2-%28sqrt%2810%29%29%2F%282%29

x+=+%282%2Bsqrt%2810%29%29%2F%282%29 or x+=+%282-sqrt%2810%29%29%2F%282%29


So the two solutions are x+=+%282%2Bsqrt%2810%29%29%2F%282%29 or x+=+%282-sqrt%2810%29%29%2F%282%29

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+2x%5E2+-+4x+-+3+=+0+
+2x%5E2+-+4x+=+3+
+x%5E2+-+2x+=+3%2F2+
Take 1/2 of the co-efficient of x,
square it and add it to both sides
+x%5E2+-+2x+%2B+%28-2%2F2%29%5E2+=+3%2F2+%2B+%28-2%2F2%29%5E2+
+x%5E2+-+2x+%2B+1+=+3%2F2+%2B+1+
+x%5E2+-+2x+%2B+1+=+5%2F2+
+%28+x+-+1+%29%5E2+=+5%2F2+
Take the square root of both sides
+x+-+1+=+sqrt%28+5%2F2+%29+
+x+=+1+%2B+sqrt%28+5%2F2+%29+
and also,
+x+=+1+-+sqrt%28+5%2F2+%29+
---------------------
I think you were correct
You can plug these answers back into the
original equation as a check- I'll leave it to you.