The expression x⁴+4 can be factorized as

8

The factors of x²-7x+6are

9

The expression (a-b)³+(b-c)³+(c-a)³ can be factorized as:

11

If 3x=a+b+c, then the value of (x-a)³+(x-b)³+(x-c)³-3(x-a)(x-b)(x-c) is

12

If (x+y)³-(x-y)³-6y(x²-y²)=ky² then k=