Question

Which equation has the solutions X=1 +-SQRT 5?

x2 + 2x + 4 = 0
x2 – 2x + 4 = 0
x2 + 2x – 4 = 0
x2 – 2x – 4 = 0

Answer 1

Answer: D

Explanation:

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Answer 2

D is correct.
`x^2-2x-4=0`

Explanation:

We are given the root of the equation

`x=1+\pm √(5)`

If we are given solution of the equation then find equation using formula.

If a and b are the solution of equation then equation would be (x-a)(x-b)=0

Here,
`a=1+√(5) , b=1-√(5)`

Equation form would be
`(x-1-√(5))(x-1+√(5))=0`

Now we simplify the above equation to get correct option.

`x^2-x+x√(5)-x+1-√(5)-x√(5)+√(5)-5=0`

`x^2-2x-4=0`

So, D is correct.
`x^2-2x-4=0`