用平方差公式展开(-x+3y)(-x-3y) （-2+3x)(-2-3x)(1\3x-y)(-1\3x-y)(x+y+4)(x+y-4)(a-b+c)(a-b-c)(x+y-3)(x-y+3)(5a+3b-2)(5a-3b+2)(2a-b+3)(2a+b-3)(a+b+c)(a-b-c)
来源：学生作业帮助网 编辑：六六作业网 时间：2024/12/19 04:50:27
用平方差公式展开(-x+3y)(-x-3y) （-2+3x)(-2-3x)(1\3x-y)(-1\3x-y)(x+y+4)(x+y-4)(a-b+c)(a-b-c)(x+y-3)(x-y+3)(5a+3b-2)(5a-3b+2)(2a-b+3)(2a+b-3)(a+b+c)(a-b-c)
用平方差公式展开
(-x+3y)(-x-3y)
（-2+3x)(-2-3x)
(1\3x-y)(-1\3x-y)
(x+y+4)(x+y-4)
(a-b+c)(a-b-c)
(x+y-3)(x-y+3)
(5a+3b-2)(5a-3b+2)
(2a-b+3)(2a+b-3)
(a+b+c)(a-b-c)
用平方差公式展开(-x+3y)(-x-3y) （-2+3x)(-2-3x)(1\3x-y)(-1\3x-y)(x+y+4)(x+y-4)(a-b+c)(a-b-c)(x+y-3)(x-y+3)(5a+3b-2)(5a-3b+2)(2a-b+3)(2a+b-3)(a+b+c)(a-b-c)
就一个平方差的公式:
（a+b)(a-b)=a*a-b*b
1.-（-x+3y)(x+3y）=（x-3y）(x+3y)=x²-9y²
2.-（3x-2）（3x+2）=-[（3x）²-2²]=4-9x²
3.(1\3x-y)(-1\3x-y)=-1\(3x-y)²
4.（x+y）²-4²=x²+2xy+y²-16
5.（a-b)²-c²=a²-2ab+b²-c²
6.（x+y-3）[x-(y-3)]=x²-（y-3）²=x²-y²+6y-9
7.(5a+3b-2)[5a-(3b-2)]=5a²-(3b-2)²=5a²-9b²+12b-4
8.[2a-（b-3)](2a+b-3)=4a²-(b-3)²=4a²-b²+6b-9
9.(a+b+c)[a-(b+c)]=a²-(b-c)²=a²-b²+2bc-c²