1 1 and 2 are two zeros of the polynomial 2x cube minus x square 5 x minus 2 find its third zero

Given polynomial
2x^3 - x^2 - 5x - 2

Let p, q and r are three zeroes of polynomial
p*q = - 1*2 = - 2.......(1)

We know,p*q*r = - d/a = -(-2)/2 = 1

p*q*r = 1......(2)

Put value of p*q from eq(1) in eq(2)
r = 1/-2 = - 1/2

Therefore, third zero is - 1/2