Question

x^3 - 7x^2 -14x +120 =0
Can some one in real basic workings show me how to work out the intercepts.

Answer 1

do you know synthetic division?

Answer 2

No sorry. I understand that I need to set x as 0 to get y intercept and y to 0 to get x intercept. Get y all ok, cant work out x when y =0

Answer 3

yeh do you have to get it into the y=(x-r)(x-s)(x-t) form ?

Answer 4

chasing intercepts. The answer is y= (0,120) and x = (-4,0) (5,0) and (6,0) just dont know how i got to the answer. Have a test tomoz

Answer 5

what did you teacher do to factor the expression as aceace^^ explained?

Answer 6

did you do long division?

Answer 7

yes

Answer 8

your teacher didn't show you synthetic division huh? that's a lot easier than long division..

Answer 9

if long division is all you got, then that's what you'll have to do...

Answer 10

that still doesnt help me. I am confused and just need some guidance and workings

Answer 11

can you show us how to do both methods please @dpalnc

Answer 12

@Bryan , you do know how to do long division right?

Answer 13

i'll assume yes so i'll just do synthetic division...

Answer 14

just as in long division, the factors that you need to "try" out comes from the factors of that constant term, +120...

Answer 15

since we know the answers already, let's assume we don't and try the factor (x - 4)..
in synthetic division we use a +4, the value that will make this factor zero, (x-4) =0...