Question

A polynomial function has a zero at x = -5. Which expression must be a factor of the polynomial?
Answer
a. x - 25
b. x + 5
c. x - 5
d. x + 25

Answer 1

this is a tricky concept i think sometimes.

if it has a zero at -5, then the factor would be (x+5) (the opposite of what you would think)

reasoning is, if you set the factor = 0 and solve for x, you would get:

x +5 = 0
x = -5

which means that it is a zero at -5

Answer 2

is x-5

Answer 3

is it?

Answer 4

not quite, if it was x - 5

then when you set x - 5 = 0

you would get x = 5, which was not the zero you were looking for.

thus, it must be x + 5, which is actually the opposite of the zero

Answer 5

o the opposite i gotcha