math help please???? 10 points!!?

Question

2. Solve by completing the square: 2x^2 + 6x - 2 = 0

is it:
[a] -3 +or- sqrt(13) /2
[b] -3 +or- 2sqrt(13) /2
[c] 3 +or- sqrt(13) / 2
[d] 3 +or- 2sqrt(13) /2

Answer 1

first of all... divide through by 2:

x^2 +3x -1 =0

x^2 +3x + _____ = 1 + _____

x^2 +3x + 2.25 = 1+ 2.25

(x+1.5)^2 = 3.25

The answer is A...

+ or - sqrt (3.25) -1.5 = [-3 + sqrt(13)]/2

It doesn't equal b, because the 2sqrt(13) /2 can be simplified to sqrt(13), and that isn't right!!

This is easiest if you just do the quadratic formula once you divide thru by 2...

Answer 2

First divide whole equation by 2 (to make like the general formula) become
x^2 + 3x - 1 = 0
Using quadratic formula (a=1,b=3,c=-1)
we get
x1= [-3+(13)^1/2]/2
x2= [-3-(13)^1/2]/2
Therefor final answer well be
[a]
x= [-3+(13)^1/2]/2
OR
x= [-3-(13)^1/2]/2

Answer 3

{-3+or- sqrt(13) }/2. If that's what you mean by (a), that's OK but the parentheses are needed.

Answer 4

the answer's are:
-(3/2)+(sqrt(13)/2) and -(3/2)-(sqrt(13)/2) and
it should be [a] or maybe there are all wrong

Answer 5

- b + - square root of b squared, - 4ac divided by 2a

= (-6 + - square root of 6 squared, - 4*2*-2 )divided by 2*2

= (-6 + - square root of 36 +16 )divided by 2*2

(-6 + - square root of 52 )divided by 2*2

(-6 + - 2 square root of 13 )divided by 2*2

dividing by 2

(-3 + - square root of 13 )divided by 2

is the formula,

the answer is a