Question

3 is a root of the equation x^2-9x+c=0
a) 12
b) 6
c) -6
d) 5

Answer 1

so what's the question? what's c?

Answer 2

i can solve this using remainder theorem...or by division of polynomials. pick your poison

Answer 3

i choose the polynomials thingy..lay it on me

Answer 4

if 3 is a root that means

x -3 is a factor so divide

______________
x-3 | x^2 - 9x + c

the remainder here should be 0..anyway moving on...
x - 6
______________
x-3 | x^2 - 9x + c
x^2 - 3x
-----------
-6x + c
-6x + 18

like i said the remainder should be 0 so

c - 18 = 0

solve for c

c = 18

that should be the answer..are you sure about the question and the chocies?

Answer 5

i can prove my answer by remainder theorem

x - 3 is a factor so

p(3) = 0

p(3) = (3)^2 - 9(3) + c = 0
9 - 27 + c = 0
-18 + c = 0

c = 18

Answer 6

soa gain are you sure it's looking for c and those are the choices>

Answer 7

so again*

Answer 8

oh yeah the question is find the other root so i got stuck with understanding wat to do with c

Answer 9

or it could be looking for the other root

Answer 10

ahh yes..i was right

Answer 11

so c = 18

x^2 - 9x + 18 = 0

one of the factors is x - 3

so divide

\[\frac{x^2 - 9x + 18}{x-3} \implies \frac{(x-3)(x-6)}{x-3}\]
do you see it?

Answer 12

yes i think i kinda get the picture i just need to load it

Answer 13

haha go for it! once you get the quotient just solve for x

Answer 14

then you have the answer. i have to go now so sorry i cannot explain further

Answer 15

but here's an example to guide you
\[\frac{(x+2)(x-1)}{x-1} \implies x + 2\]

solve for x

x + 2 = 0
x = -2

Answer 16

can i just ask the questions ? is sensible to replace 0 with 3?

Answer 17

hello @lgbasallote ?

Answer 18

what do you mean?

Answer 19

like this x^2-9x+c=3

Answer 20

no it's not sensible

Answer 21

if it's x^2 - 9x + c -3 = 0 then it's sensible to do that

Answer 22

okay i really have to go. good luck!

Answer 23

i need it