Question

Solve x2 + 2x + 9 = 0 can someone please help me!!

Answer 1

`x=-1+2√(2)i,\:x=-1-2√(2)i`

Explanation:

We have been given the quadratic equation
`x^2+2x+9=0`

The quadratic formula is given by

`x_(1,\:2)=(-b\pm √(b^2-4ac))/(2a)`

Comparing the given equation with
`ax^2+bx+c=0`

`a=1,\:b=2,\:c=9`

Substituting the known values, we get

`x_(1,\:2)=(-2\pm √(2^2-4\cdot \:1\cdot \:9))/(2\cdot \:1)\\\\(-2\pm√(32)i)/(2\cdot \:1)\\\\(-2\pm4√(2)i)/(2)\\\\-1\pm2√(2)i`

Hence, the values of x are

`x=-1+2√(2)i,\:x=-1-2√(2)i`

Answer 2

use quadratic formula

for ax^2+bx+c=0

x=
`(-b+/- √(b^2-4ac) )/(2a)`

1x^2+2x+9=0
a=1
b=2
c=9
remember
i=√-1 or
i²=-1


x=
`(-2+/- √(2^2-4(1)(9)) )/(2(1))`
x=
`(-2+/- √(4-36) )/(2)`
x=
`(-2+/- √(-32) )/(2)`
x=
`(-2+/- 4√(-2) )/(2)`
x=
`(-2+/- 4√(-2) )/(2)`
x=
`(-2+/- 4i√(2) )/(2)`
x=
`-1+ 2i√(2)` or
`-1- 2i√(2)`