Question

If two of the zeros of the cubic polynomial ax³ + bx² + cx + d are each equal to zero, then the third zero is
A. -d/a
B. c/a
C. -b/a
D. b/a

Answer 1

1.Two of the zeros of the cubic polynomial ax³ + bx² + cx + d are each equal to zero.

2. Let p,q,r be the zeros of given equation.

3. Given that two of the zeros are equal to zero. So, let p+q =0.

4.But we know that, sum of all the zeros equal to - b/a in cubic equation.

5. So, p+q+r= - b/a

6. As p+q =0,

hence r = - b/a

So, option C is the correct answer.