Question

Solve this quadratic equation by completing the square.

x^2+6x=18


`x = - 3 + √(27)`

`x = - 3 + \sqrt18`

`x = - 6 + √(27)`

`x = - 6 + √(18)`

please help​

Answer 1

Option A.

Explanation:

The given equation is

`x^2+6x=18`

We need to find the roots using completing the square.

`\left((b)/(2)\right)^2=\left((6)/(2)\right)^2=3^2=9`

Add 9 on both sides in the given equation to make it perfect square.

`x^2+6x+9=18+9`

`x^2+2(x)(3)+3^2=27`

`(x+3)^2=27`

Taking square root on both sides.

`x+3=√(27)`

Subtract 3 from both sides.

`x=-3+√(27)`

Therefore, the correct option is A.