Question

What is the positive solution to the equation 0 = –x2 + 2x + 1?

Quadratic formula: x =

–2 +
2 –
1 +
–1 +

Answer 1

1±√2

Explanation:

To solve the quadratic, use the quadratic formula. Substitute a = -1, b = 2 and c = 1.

The quadratic formula is
`x=(-b+/-√(b^2-4ac) )/(2a)`.

Substitute and you'll have:

`x=(-b+/-√(b^2-4ac) )/(2a) =(-2+/-√(2^2-4(-1)(1)) )/(2(-1))=(-2+/-√(4+4) )/(-2))`

`(-2+/-√(8) )/(-2)=(-2+/-2√(2) )/(-2) = 1 +/- √(2)`