b²-(a-b+c)²=(a+c)(2b-a-c)(2x+y)²-(2x-y)²=8xy
x+y=0(x+2)²-(y+2)²=(x+y+4)(x-y)=4 x=1/2y=-1/2
4x³-x=x(2x+1)(2x-1)(x+y)²-9x²=(4x+y)(y-2x)
2012²-144=(2012+12)(2012-12)=4048000
(5又3/4)²-(2又1/4)²=(5又3/4+2又1/4)(5又3/4-2又1/4)=28
100²-99²+98²-97²+……+2²-1
=(100+99)(100-99)+(98+97)(98-97)+…+(2+1)(2-1)
=100+99+98+97+…+2+1=5050(x+y)²-9x²=(4x+y)(y-2x)这个过程能详细点么平方差公式(x+y)²-9x²=(x+y)²-(3x)²=(4x+y)(y-2x)