Question

11) Which of the following is zero of the polynomial x^3+x^2+x+1

1
-1
both options 1 and 2
None​

Answer 1

x = - 1

Explanation:

Given

f(x) = x³ + x² + x + 1

If x = 1 is a factor then f(1) = 0

f(1) = 1³ + 1² + 1 + 1 = 4 ≠ 0 , thus x = 1 is not a zero

f(- 1) = (- 1)³ + (- 1)² + (- 1) + 1 = - 1 + 1 - 1 + 1 = 0

Thus x = - 1 is the only zero