Question

If two of the zeros of the cubic polynomial ax³ + bx² + cx + d are each equal to zero, then the third zero is

Options

• \[\frac{- d}{a}\]
• \[\frac{c}{a}\]
• \[\frac{- b}{a}\]
• \[\frac{b}{a}\]

Answer 1

Let `alpha = 0, beta=0` and y be the zeros of the polynomial

f(x)= ax³ + bx² + cx + d 

Therefore

`alpha + ß + y= (-text{coefficient of }X^2)/(text{coefficient of } x^3)`

`= -(b/a)`

`alpha+beta+y = -b/a`

`0+0+y = -b/a`

`y = - b/a`

`\text{The value of}  y - b/a`

Hence, the correct choice is `(c).`