Question

Given that 7 is a zero of h(x)=x^3-7x^2-3x+21, find the other zeros.

Answer 1

x= 7 x = ±√3

Explanation:

h(x)=x^3-7x^2-3x+21

Factor by grouping

h(x) = x^2( x-7) -3 (x-7)

Factor out an (x-7)

h(x) = (x-7) ( x^2 -3)

Using the zero product property

0= (x-7) ( x^2 -3)

x-7 =0 x^2 -3 =0

x=7 x^2 =3

x= 7 x = ±√3