1、 3(-a+1)(-a-1)-2(a+1)^2 2、 (3x-2y)^2 3、 (3x-2y)^2(3x+2y)^2(9x^2+4^2)^2

问题描述:

1、 3(-a+1)(-a-1)-2(a+1)^2 2、 (3x-2y)^2 3、 (3x-2y)^2(3x+2y)^2(9x^2+4^2)^2
4、(x-2y)^2n/(2y-x)^2n-1+(2x-y)(-2x-y)+(x-y)(-x+y)
5、3.7654^2+0.4692*3.7654+0.2346^2
那个是1、 2、 3、题号。不是题里面的符号。

1、 3(-a+1)(-a-1)-2(a+1)²
=3(a²-1)-2(a²+2a+1)
=3a²-3-2a²-4a-2
=a²-4a-5
2、 (3x-2y)²
=(3x)²-2*3x*2y+(2y)²
=9x²-12xy+4y²
3、 (3x-2y)²(3x+2y)²(9x²+4y²)²
=(9x²-4y²)²(9x²+4y²)²
=(81x^4-16y^4)²
=6561x^8-2592x^4y^4+256y^8
4、(x-2y)^2n/(2y-x)^2n-1+(2x-y)(-2x-y)+(x-y)(-x+y)
=-(x-2y)^2n/(x-2y)^2n-1-(2x-y)(2x+y)-(x-y)(x-y)
=-(x-2y)-4x²+y²-x²+2xy-y²
=-x+2y-5x²+2xy
5、3.763.7654^2+0.4692*3.7654+0.2346^2
=3.7654^2+2*0.2346*3.7654+0.2346^2
=(3.7654+0.2346)^2
=4^2
=16