Question

Find the zeros of the polynomial function.





f(x) = x2 – 12x + 20




4, 5



2, 10




–4, –5



–2, –10

Answer 1

You posted this earlier and I responded in depth. Why are y ou posting this question again? I'm not eager to repeat what I typed earlier in an effort to help you.

Answer 2

Just set the problem equal to 0 and solve for x ^-^

Answer 3

Do you know how to factor? >_>

Answer 4

x^2 -12x+20=0
x^2-12x=-20
now once i get to this point what should i do

Answer 5

The quadratic formula also works.\[f(x)=ax^{2}+bx-c\rightarrow x=\frac{-b\pm\sqrt{b^{2}-4ac}}{2a}\]

Answer 6

Oh, you're completing the square?

Answer 7

Keep this equation as given: x^2 -12x+20=0 It does not help to move that 20 to the right side.

Answer 8

Yes, what @mathmale said... completing the square doesn't help you find the zeros. I believe it only helps you find the vertex form of a quadratic function

Answer 9

As I shared with you earlier, methods of solving this equation include:
1. graphing
2. completing the square
3. factoring
4. quadratic formula
5. factoring by grouping

Please identify the approach that YOU want to use.

Answer 10

But this is a simple question. All you need to do is factor to find the 0's.

Answer 11

Yes: that'd be the easiest approach. But learning to use other approaches would be helpful as well.

Answer 12

I meant to send that in reply to kitti, my apologies :P

Answer 13

xD
Well, the quadratic formula also works as the "long way round" when you can't factor or get stuck doing that... ^-^

Answer 14

Oh, so you CAN use completing the squ- wait yeah I'm dumb lol

Do you know how to continue solving using complete the square?

Answer 15

@ayonnaleflore: Your input, please? Questions? Comments?

Answer 16

Yes, completing the square would definitely "work" here. But: factoring would be the fastest method.

Answer 17

no i dont know how to continue by completing the square @kittiwitti1

Answer 18

http://www.purplemath.com/modules/sqrquad.htm

Answer 19

Then please cross that off the list.

Which other method would you like to use?

Answer 20

The link I posted helps with completing the square, but you can also use other options, as we have said before ☻

Answer 21

factoring by grouping but im not sure how to do that

Answer 22

As I shared with you earlier, methods of solving this equation include:
1. graphing
2. completing the square
3. factoring
4. quadratic formula
5. factoring by grouping

Please identify the approach that YOU want to use.

Answer 23

so how would i start it off???

Answer 24

I don't think you can factor by grouping when there's a trinomial (three terms). I thought it required four terms.. :\

Answer 25

wait doesn't it need four terms to factor by grouping

Answer 26

lol yeah, my question exactly xD

Answer 27

ok so how about factoring??

Answer 28

You can "make" four terms during factoring by grouping.

Separate -12x into two parts that combine to produce -12x.

Factor by grouping.

Or, if you prefer, just factor. How would you do that?

Hint: What are possible factors of 20?

Answer 29

Oh right. I suppose you could do that