(1) (2m+3)(2m-3)
问题描述:
(1) (2m+3)(2m-3)
(2) x(x+1)+(2-x)(2+x)
(3) (3x-y)(3x+y)+y(x+y)
(4) (a+二分之一b)(a-二分之一b)-(3a-2b)(3a+2b)
答
(1) (2m+3)(2m-3)=4m²-9(2)x(x+1)+(2-x)(2+x)=x+4 (3)(3x-y)(3x+y)+y(x+y)=9x²-y²+xy+y²=9x²+xy (4)(a+二分之一b)(a-二分之一b)-(3a-2b)(3a+2b)=a²-b&sup...