Bonjour
3a - (3a - 1)(3a + 1)
= 3a - [(3a)^2 - 1^2]
= 3a - 9a^2 + 1
= -9a^2 + 3a + 1
(2x - 4) * 3 - 4(2x + 4)
= 6x - 12 - 8x - 16
= -2x - 28
(2x - 5)[3 + 3(1 + 3x)]
= (2x - 5)(3 + 3 + 9x)
= (2x - 5)(6 + 9x)
= 12x + 18x^2 - 30 - 45x
= 18x^2 - 33x - 30
(x - 2)(x - 3) - x^2
= x^2 - 3x - 2x + 6 - x^2
= -5x + 6
5[(3 - 2a) * 5]
= 5(15 - 10a)
= 75 - 50a
(x - 1) - (x - 5) - (x - 1)(x - 5)
= x - 1 - x + 5 - (x^2 - 5x - x + 5)
= 4 - x^2 + 6x - 5
= -x^2 + 6x - 1
[1 + 3(2x - 1)][1 - 3(2x + 1)]
= (1 + 6x - 3)(1 - 6x - 3)
= (6x - 2)(-6x - 2)
= (-2 + 6x)(-2 - 6x)
= (-2)^2 - (6x)^2
= 4 - 36x^2
(3a - h) - 5(2a - 3h)
= 3a - h - 10a + 15h
= -7a + 14h
