SOLUTION: i have to find the solution... 2x^2+6x+5=0 i have tried it with the completed square which means 2x^2+6x+9 = -5+9 at the end i was with (2x+3)(x+3)=4 no complete square... then

Question 193042: i have to find the solution... 2x^2+6x+5=0
i have tried it with the completed square which means 2x^2+6x+9 = -5+9
at the end i was with (2x+3)(x+3)=4 no complete square...
then i tried to divide it by 2 so i had x^2 +3x+4.5=2
but with 4.5 i am not getting a complete square either...
Now i don't know any further... PLEASE help me!
Anna
Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
i have to find the solution... 2x^2+6x+5=0
i have tried it with the completed square which means 2x^2+6x+9 = -5+9
at the end i was with (2x+3)(x+3)=4 no complete square...
then i tried to divide it by 2 so i had x^2 +3x+4.5=2
but with 4.5 i am not getting a complete square either...
-------------
Dividing by 2 is the best approach.
x^2 +3x+2.5=0 Start from here
x^2 + 3x + 2.25 = -0.25
(x + 1.5)^2 = -0.25
x+1.5 = +0.5i
x+1.5 = -0.5i
--------------
x = -3/2 + i/2
x = -3/2 - i/2
------------

Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)

Quadratic equation (in our case ) has the following solutons:

For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

The discriminant -1 is less than zero. That means that there are no solutions among real numbers.

If you are a student of advanced school algebra and are aware about imaginary numbers, read on.

In the field of imaginary numbers, the square root of -1 is + or - .

The solution is , or
Here's your graph:

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