(x1+x2)平方-4x1x2
=x1²+2x1x2+x2²-4x1x2
=x1²-2x1x2+x2²
=(x1-x2)²
(x平方+2)平方-(2x-1)平方
=(x²+2+2x-1)(x²+2-2x+1)
=(x²+2x+1)(x²-2x+3)
=(x+1)²(x+1)(x-3)
=(x+1)³(x-3)
(x1+x2)平方-4x1x2
=x1²+2x1x2+x2²-4x1x2
=x1²-2x1x2+x2²
=(x1-x2)²
(x平方+2)平方-(2x-1)平方
=(x²+2+2x-1)(x²+2-2x+1)
=(x²+2x+1)(x²-2x+3)
=(x+1)²(x+1)(x-3)
=(x+1)³(x-3)