Question

How do you solve `x^2+8x+18 = 0` by completing the square?

Answer 1

No Solution

Explanation:

To complete the square, we need the perfect square of the equation of `x^2+8x+18` In order to find the perfect square, we need to change the equation into `(x-b)^2=a`, were a and b are constants. To find c, we divide the coefficient by 2 and square it

`(8/2)^2=16`

We get 16, which means that we must change our current equation to have a 16.

`x^2+8x+18-2=-2`

By subtracting 2 from both sides, we get that 16. Now, we can simplify the left hand side into the perfect square

`x^2+8x+16=(x+4)^2`

This means `(x+4)^2=-2`

We now square root both side, giving us `x+4=sqrt-2`

They can never be a negative square root, so therefore there is no answer.