1.
x³-1=(x-1)(x²+x+1) 立方差公式
2.
2a^2+4ab+2b^2
=2(a²+2ab+b²)
=2(a+b)²
3.
(xy)²-1
=(xy+1)(xy-1)
4.
(x-y)^2+4xy
=x²-2xy+y²+4xy
=x²+2xy+y²
=(x+y)²
5.
2x(a-2)-y(2-a)
=2x(a-2)+y(a-2)
=(a-2)(2x+y)
1.
x³-1=(x-1)(x²+x+1) 立方差公式
2.
2a^2+4ab+2b^2
=2(a²+2ab+b²)
=2(a+b)²
3.
(xy)²-1
=(xy+1)(xy-1)
4.
(x-y)^2+4xy
=x²-2xy+y²+4xy
=x²+2xy+y²
=(x+y)²
5.
2x(a-2)-y(2-a)
=2x(a-2)+y(a-2)
=(a-2)(2x+y)