Question

Factor 6x^9-30x^7

Answer 1

what is the common factor of 6 and 30, and what is the common factor of x^9 and x^7 ?

Answer 2

Ok that is what i thought i should be doing. It is 3x^7

Answer 3

30/6 = 5 right? so your number factor is 6....x^7 is another factor , that's correct, but after that you can still factor again..can you write them out?

Answer 4

my answer would be 6x^7(1+5x^2)?

Answer 5

shouldn't it be - instead of + ?

Answer 6

also the x^2 is with the coefficient 6...not 30 :)

Answer 7

yes it should lol negative!

Answer 8

so it would be 6x^7(5x^2-1)

Answer 9

no :) if you try to multiply in again...you will get 30x^9 ...is your first term, and that wouldn't be true with your original expression. right? :)

Answer 10

right. so where am I messing up at?

Answer 11

6x^7(5-x^2)

Answer 12

when you factor, try to do each term carefully. ..first take out the 6 see what's inside, then take out the x^7 ...then see what's left
write like this, straight down so you can see it easily

6x^9 - 30x^7
= 6x^7( x^2 - 5)
= 6x^7{[x - sqrt(5)(x + sqrt(5)]}


the last step is from formula : a^2 - b^2 = (a - b)(a + b)

you got that right?

Answer 13

I typed you my awnser was that correct?

Answer 14

your answer was not correct, because you switch the term around inside the parenthesis

Answer 15

when you factor, each step, if you go backward and multiply in, you should get the previous step correctly

Answer 16

so I should have 6x^7(x^2-5)

Answer 17

yeah, that or go further one more step as i typed earlier.

Answer 18

i dont get your next step.

Answer 19

6x^7(x^2-5)(x^2+5) ?

Answer 20

no no, when you get to ...6x^7(x^2 - 5)...

to use formular a^2 - b^ = (a - b)(a + b) ......look at x^2 - 5
your x = a (so x^2 = a^2)
your b = sqrt(5) (squareroot of 5) ...so that your b^2 = 5

you get this ? i must go in couple mins. i want to help you through this so let me know soon

Answer 21

as i did earlier for you : this is it...you can check again : (i'll copy and paste the earlier work)

6x^9 - 30x^7
= 6x^7( x^2 - 5)
= 6x^7{[x - sqrt(5)(x + sqrt(5)]}

Answer 22

hope you enjoy :) and have a good evening. i must go now