Question

Algebra 2 Help please!!
which of the following represents the zeros of f(x)=x^3-11x^2+38x-40
a) 5, -4, 2
b) 5, -4, -2
c) 5, 4, 2
d) 5, 4, -2

Answer 1

Zeros of a problem is when you want f(X)=0. Right?

Answer 2

This problem is very simple. Finding the zeros of a function, we want to find any 'x' value(s) that will make the function = 0.

Answer 3

I think so. I'm not sure >.< I really have no idea how to do this.

Answer 4

In this case, you are given MC answers that you can put into your problem. I'll do the first on for you. :-)

Answer 5

Oh okay that makes sense!

Answer 6

thank you

Answer 7

Glad it does :-)

Answer 8

Without MC answers to help, you would factor to find the zeros.

Answer 9

So I'm basically plugging in the 3 numbers for x and finding which of them all make it f(x)=0?

Answer 10

f(x)=x^3-11x^2+38x-40
a) 5, -4, 2
b) 5, -4, -2
c) 5, 4, 2
d) 5, 4, -2
5^3-11(5)^2+38(5)-40=0. This satisfies what we are looking for, so 5 is a zero to the function.

Answer 11

f(-4)= -4^3-11(-4)^2+38(-4)-40=-432 this doesn't satisfy, so -4 doesn't work.

Answer 12

Brb, I have to do something.

Answer 13

well that narrows it down, I can figure out if it's 2 or -2 and I'll let you know.

Answer 14

nvmd I guess I did something wrong cause neither of them came out as 0

Answer 15

I am back @notamathgenuis

Answer 16

yay!

Answer 17

Actually, 2 produces a zero.

Answer 18

f(x)=x^3-11x^2+38x-40
a) 5, -4, 2 (not zero function)
b) 5, -4, -2(not zero function)
c) 5, 4, 2
d) 5, 4, -2
Now its 50/50.
Since we know its both 5 and 4, lets try -2 and 2.
2 first.
2^3-11(2)^2+38(2)-40=0 when f(x)=f(2)

Answer 19

-2^3-11(-2)^2+38(-2)-40=-168. Not z ero.

Answer 20

c) is the only one to satisfy.

Answer 21

oh okay I see what I did wrong!! thank you so much.

Answer 22

We learn math through mistakes. I am in Pre-Calc/Trig, and have made many, many mistakes but learned from them! That's how we gotta learn :-) If you need any more help, mention me. I LOVE Algebra.

Answer 23

I will definitely mention you on anything else I need help with. I HATE algebra! lol

Answer 24

Fantastic, Algebra II was my favorite course. You sound like my brother, he doesn't care for it too much, haha :)