Question

a.(3x-1)³ - (3x+1)³

b.(1+3x)³ - (1-3x)³

c.(1+3x)³ - (1-3x).(1+3x)-(1-3x)³

Answer 1

`a, (3x-1)^3-(3x+1)^3`

`= (3x-1-3x-1)(9x^2-6x+1+9x^2-1+9x^2+6x+1`

`= (-2)(27x^2 +1)`

`= -54x^2-2`.

`b, (1+3x)^3 - (1-3x)^3`

`= 1+ 9x + 27x^2 + 27x^3 - 1 + 9x - 27x^2 + 27x^3`

`= 54x^3 + 18x`.

`c, = 54x^3 + 18x -1 +9x^2`.

Answer 2

a: =27x^3-27x^2+9x-1-27x^3-27x^2-9x-1

=-54x^2-2

b: =27x^3+27x^2+9x+1-27x^3+27x^2-9x+1

=54x^2+2

c: =54x^2+2+(3x-1)(3x+1)

=54x^2+2+9x^2-1

=63x^2+1