Question

find the value of k so that the remainder of (x^3+5x^2-4x+k)/(x+5) is 0

Answer 1

you are dividing by x+5
so x+5=0 when x=-5
so plug in -5 into the top polynomial and set it equal to 0
that is if f(x)=x^3+5x^2-4x+k
then f(-5)=0 <--solve this equation for k

Answer 2

5=k? 0=k? @freckles

Answer 3

what is f(-5)?

Answer 4

replace the x's in x^3+5x^2-4x+k with (-5)'s

Answer 5

that is called f(-5)
then we know that should be equal to 0 since we are given f(-5)=0

Answer 6

so k=0? @freckles

Answer 7

really don't see how you get k=0

Answer 8

\[(-5)^3+5(-5)^2-4(-5)+k=0 \]
I don't think this will give you k=0

Answer 9

wait k=45?

Answer 10

go through it slowly

Answer 11

(-5)^3=-125
5(-5)^2=125
-4(-5)=20

Answer 12

-125+125+20+k=0

Answer 13

so many -20

Answer 14

yeah

Answer 15

so its -20

Answer 16

@freckles

Answer 17

yes?