How do you find the zeroes of f(x)= x^3 - 17x^2 + 81x -65f(x)=x317x2+81x65?

1 Answer
Mar 3, 2018

Zeros are x=1 , x= 8-1i and x= 8+1i x=1,x=81iandx=8+1i

Explanation:

f(x)=x^3-17x^2+81x-65 f(x)=x317x2+81x65 or

f(x)=x^3-x^2-16x^2+16x+65x-65 f(x)=x3x216x2+16x+65x65 or

f(x)=x^2(x-1)-16x(x-1)+65(x-1)f(x)=x2(x1)16x(x1)+65(x1) or

f(x)=(x-1)(x^2-16x+65) :. x=1 is one zero

f(x)= x^2-16x+65 or

f(x)= x^2-16x+64 +1 or

f(x)= (x-8)^2 - (i^2) [i^2=-1] or

f(x)= (x-8+ i)(x-8-i) :. . Other zeros are

x= 8-1i and x= 8+1i

Zeros are x=1 , x= 8-1i and x= 8+1i [Ans]