Question

Help!!!! I will fan and give medals!!!! Help!!!

Find the zeros of the polynomial function.


f(x) = x2 + 9x + 20

Answer 1

I would try to factor it.

step 1:
list all pairs of numbers that when you multiply them, you get 20

can you do that ?

Answer 2

Get a hint from the plot
http://www.wolframalpha.com/input/?i=plot++x%5E2+%2B+9x+%2B+20+from+x+%3D+-6+to++x%3D-3

Answer 3

Notcie that
4+5=9
4(5)=20
Can you factor it now?

Answer 4

i dont understand

Answer 5

Notice that
\[
(a+x) (b+x)=x^2 +a x+b x+ a b=x^2+ (a+b)x+ a b
\]

Answer 6

Your a=4 and your b=5

Answer 7

\[
x^2+9 x+20=(x+4) (x+5)=0
\]
For which valuee your ploynomial is zero?

Answer 8

Can you finish it?

Answer 9

no ive never done this

Answer 10

The zeros are x=-4 and x=-5. If you replace x by -4 or x by -5, your polynomial would be equal to zero

Answer 11

A.
2, 10

B.
–4, –5

C.
–2, –10

D.
4, 5

Answer 12

\[
(-4)^2 + 9(-4) +20= 16-36 +20=0\\
(-5)^2 + 9(-5) +20=25-45+20=0

\]

Answer 13

so B.

Answer 14

B is your answer

Answer 15

Yes

Answer 16

can you help me with more please

Answer 17

Post it as new problem and tag me in it

Answer 18

ok