Carcass wrote:
If \((1 − p)\) is a root of quadratic equation \(x^2 + px + (1 − p) = 0\) then its roots are
A. 0, -1
B. -1, 1
C. 0, 1
D. -1, 2
E. 2, 3
Kudos for the right answer and explanation
If (1 − p) is a
root, then
x = (1 − p) is a
solution to the equation x² + px + (1 − p) = 0
Replace x with
(1 - p) to get:
(1 - p)² + p
(1 - p) + (1 - p) = 0
Factor out the (1 - p) to get: (1 - p)[(1 - p) + p + 1] = 0
Simplify: (1 - p)[2] = 0
So, p =
1If p =
1, our equation, x² + px + (1 − p) = 0, becomes x² + (
1)x + (1 −
1) = 0
Simplify: x² + x = 0
Factor: x(x + 1) = 0
So, EITHER x = 0 OR x = -1
Answer: A
Cheers,
Brent