87,650vs3,633

[0513 #774-UNKNOWN 2023/07/23(日) 19:08:08.22 ID:2tewvu1L0]

x2+(a+b)x+ab=(x+a)(x+b)
x2+2xy+y2=(x+y)2
x2−2xy+y2=(x−y)2
x2−y2=(x+y)(x−y)