Question

Show that -1 and 4 are zeros of the polynomial x^3-13x-12.Also find the third zero.

Answer 1

Answer:

x^3-13x =12.

Case1:- Put x= -1 in eqn

(-1)^3 -13(-1)=12

12= 12

Case2:- Put x= 4 in eqn

64-52 =12

12=12

Third zero is x=3

Hope U satisfied with the answer

Answer 2

Step-by-step explanation:

Let,P(x) = x↑3-13x-12

Now,P(-1) = -1+13-12 =0

P(4) = 64-52-12 = 0

Here, P(-1)=P(4)=0

therefore, -1 and 4 are zeroes of P(x)

Here,(x+1) and (x-4) become factors of P(x)

(x+1)(x-4),i.e,x↑2-3x-4 is also a factor of P(x).

Now, divide P(x) by x↑2-3x-4 for next root.

After dividing by using polynomial division metod..We get x = -3 as the third root.