Question

This one i am really stuck with
(3x-2)^3-27

Answer 1

what are you supposed to do?

Answer 2

sorry factor

Answer 3

This is a difference of two cubes. We can see this because:
\[(3x-2)^3-27 \Leftrightarrow (3x-2)^3-3^3\]

Answer 4

so you want to use the formula:
\[a^3-b^3 = (a-b)(a^2+ab+b^2), a = 3x-2, b = 3\]

Answer 5

\[(3x-2)^3-27=(3x-2)^3-3^3=(3x-2-3)((3x-2)^2+3(3x-2)+3^2)\]
etc.

Answer 6

ok, i used the difference of cubes and now i have (3x-2)(9x^2+6x+4)-27
how do i get the 27 out of there

Answer 7

when you use the difference of two cubes, you should have any terms sticking out like that. that -27 probably doesnt belong there.

Answer 8

shouldnt*

Answer 9

ok i see what i'm doing wrong