а) (2a+3)(a-3) - 2a(4+a)= 2a^2 + 3a - 6a - 9 - 8a= 2a^2 - 11a - 9 - 8a= 2a^2 - 19a - 9
б) (1-x)(x+1)(x-1)^2= (1-x)(x+1)(x^2 - 2x + 1)= (1-x)(x^3 - 2x^2 + x + x - 2x + 1)= (1-x)(x^3 - 2x^2 + x + x - 3x + 1)= (1-x)(x^3 - 2x^2 - 2x + 1)= x^3 - 2x^2 - 2x + x - x^3 + 2x^2 + 2x -1= x - 1
в) (a+b)(a-2b) + (2b-a)(2b+a)= a^2 - 2ab + ab - 2b^2 + 4b^2 - 2a^2 + 2ab - a^2= a^2 - 3a^2 - 2b^2 + 4b^2= -2a^2 + 2b^2
г) (3x + 2)^2 - (3x - 1)^2= 9x^2 + 6x + 6x + 4 - 9x^2 + 6x - 6x - 1= 12x + 4 + 6x - 1= 18x + 3
а) (2a+3)(a-3) - 2a(4+a)
= 2a^2 + 3a - 6a - 9 - 8a
= 2a^2 - 11a - 9 - 8a
= 2a^2 - 19a - 9
б) (1-x)(x+1)(x-1)^2
= (1-x)(x+1)(x^2 - 2x + 1)
= (1-x)(x^3 - 2x^2 + x + x - 2x + 1)
= (1-x)(x^3 - 2x^2 + x + x - 3x + 1)
= (1-x)(x^3 - 2x^2 - 2x + 1)
= x^3 - 2x^2 - 2x + x - x^3 + 2x^2 + 2x -1
= x - 1
в) (a+b)(a-2b) + (2b-a)(2b+a)
= a^2 - 2ab + ab - 2b^2 + 4b^2 - 2a^2 + 2ab - a^2
= a^2 - 3a^2 - 2b^2 + 4b^2
= -2a^2 + 2b^2
г) (3x + 2)^2 - (3x - 1)^2
= 9x^2 + 6x + 6x + 4 - 9x^2 + 6x - 6x - 1
= 12x + 4 + 6x - 1
= 18x + 3