Question

Complete the square to solve the equation below check all that apply x^2+8x-2=18

Answer 1

x^2+8x-2=18

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

x^2+8x-20= 0

(x-2)(x+10)=0

x-2= 0 , x+10=0

x-2+2= 0+2, x+10-10= 0-10

x=2 , x=-10

Answers are x= 2 -B, x=-10 -A.

Answer 2

Option A and B

Explanation:

Given : Quadratic equation
`x^2+8x-2=18`

To find : Complete the square to solve the equation below check all that apply ?

Solution :

Re-write,
`x^2+8x-2=18`

`x^2+8x-20=0`

Applying quadratic formula,

`x=(-b\pm√(b^2-4ac))/(2a)`

Here, a=1 , b=8, c=-20

`x=(-8\pm√(8^2-4(1)(-20)))/(2(1))`

`x=(-8\pm√(64+80))/(2)`

`x=(-8\pm√(144))/(2)`

`x=(-8\pm12)/(2)`

`x=-4\pm6`

`x=-4+6,-4-6`

`x=2,-10`

The solution of the equation is x=2,-10.

Therefore, Option A,B satisfy the equation.