Px x4 5x2 6 a Find all zeros of P real and complex Enter yo
 P(x) = x4  5x2  6
 (a) Find all zeros of P, real and complex. (Enter your answers as a comma-separated list. Enter all answers including repetitions.)
x =
 (b) Factor P completely.
P(x) =
Solution
P(x) = x^4 - 5x^2 -6
substitute x^2 = y
So, we have y^2 - 5y -6
y^2 - 6y +y -6
y(y -6) +1( y -6)
(y+1)(y -6)
y = -1 ; x^2 =-1 ; x = i , -i
y = 6 ; x^2 = 6 ; x = sqrt6 , -sqrt6
So, solution : x = i , -i , sqrt6 , -sqrt6
P(x) = (x +i)(x -i)(x -sqrt6)(x +sqrt6)

