Question

How do i determine a formula for the polynomial function whose graph has zeros (x+5) ( x +1) (x-4) and a y intercept of -40

Answer 1

it looks like you have it already. only one step left

Answer 2

i assume you mean the zeros are -5,-1 and 4

Answer 3

i tried f(x) = -40 (x+5).... etc
yes those are the zeros

Answer 4

the only thing you don't have is the leading coefficient
so write
\[p(x)=a(x+5) ( x +1) (x-4) \] then you know
\[p(0)=-40\] so write
\[a(5\times 1\times -4)=-40\] and solve for \(a\)

Answer 5

a= 2

Answer 6

clear or no? y intercept is what you get when \(x=0\)
yes, it is 2

Answer 7

how do i write that out

Answer 8

2x^3 + 5x^2 + x

Answer 9

not sure what you mean. you have it

Answer 10

oh you mean how to you multiply out? you just have to grind it til you find it. do a bunch of multiplications, or else cheat

Answer 11

ohhh ok .. 2(x+5)(x+1)(x-4) then yeah.. from there i guess i need to do the math.. thats no prob though.. thanks a lot

Answer 12

http://www.wolframalpha.com/input/?i=2%28x%2B5%29+%28+x+%2B1%29+%28x-4%29

Answer 13

yes, as they say "do the math"
i like cheating, that way i know it is right

Answer 14

yes that looks like my graph too.. haha. thank you

Answer 15

yw