Question

If-1 is a root of f), which of the following must be true?

Answer 1

Answer:

A factor of f(x) is (x + 1).

Step-by-step explanation:

When we put x+1= 0 then we  get the value x= -1

This value is then put into the function to find out whether it is a root or not. For a root  to exist it must not have a remainder or the remainder must be zero.

Suppose the function is

F(x)= 2x³ - 42x - 40

f(-1)= 2(-1)³ - 42(-1) - 40

f(-1)= -2 + 42- 40

f(-1)= 0

This gives -1 as the root of the function.