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. \(\frac{-d}{a}\)

B. \(\frac{c}{a}\)

C. \(\frac{-b}{a}\)

D. \(\frac{b}{a}\)

Answer 1

Given,

ax³ + bx² + cx + d

By Putting x = 0

0 + d = 0

d = 0

ax³ + bx² + cx + d = 0

x(ax² + bx + c) = 0

Put x = 0 c = 0

ax² + bx = 0

x(ax + b) = 0

Hence,

x = – b/a