Question

(a+2b-3)(a-2b+3) (2x-y)(3x-2y)+(y-x)(2x-5y) (2x-1)(2x+1)(x^2+x+1)

谢谢要过程
【1】(a+2b-3)(a-2b+3) 【2】(2x-y)(3x-2y)+(y-x)(2x-5y) 【3】(2x-1)(2x+1)(x^2+x+1)

Answer 1

(a+2b-3)(a-2b+3)
=[a+(2b-3)][a-(2b-3)]
=a²-(2b-3)²
=a²-4b²+12b-9

(2x-y)(3x-2y)+(y-x)(2x-5y)
=6x²-7xy+2y²-5y²-2x²+7xy
=4x²-3y²

(2x-1)(2x+1)(x^2+x+1)
=(4x²-1)(x²+x+1)
=4x^4+4x³+4x²-x²-x-1
=4x^4+4x³+3x²-x-1 这个是对的 因为涐做的跟一楼做的一样 所以百分之90是对的吧

Answer 2

(a+2b-3)(a-2b+3)
=[a+(2b-3)][a-(2b-3)]
=a²-(2b-3)²
=a²-4b²+12b-9

(2x-y)(3x-2y)+(y-x)(2x-5y)
=6x²-7xy+2y²-5y²-2x²+7xy
=4x²-3y²

(2x-1)(2x+1)(x^2+x+1)
=(4x²-1)(x²+x+1)
=4x^4+4x³+4x²-x²-x-1
=4x^4+4x³+3x²-x-1

Answer 3

（a+2b-3)(a-zb+3)=[a(2b-3)][a-(2b-3)]=a^2-(2b-3)^2=a^2-4b^2+12b-9