What are the zeros of the polynomial function? f(x)=x^4−4x^3−22x^2+4x+21 ( pick more then 1) select each correct answer. −3 −1 0 1 3 7

7, -3 , -1 and 1  are  zeroes of the function

Step-by-step explanation:

By the rational roots theorem as the last term = 21 and coefficient of x^4 = 1  +/- 3 or +/- 7 may be roots Try x = 7:-

f(7) = 7^4 - 4(7)^3 - 22(7)^2 + 4(7) + 21 =  0

so x = 7 is a root

Also try x = -3  f(-3) = 0  so -3 is a root also.

There may be 2 more real roots ( as its an equation in x^4)

f(1) = 0 and f(-1) = 0  so 1 and -1 also roots