✨ Jawaban Terbaik ✨
(1)x+y=Aとおく
A²-4A+3
=(A-1)(A-3)
=(x+y-1)(x+y-3)
(2)
9a²-(b²-4bc+4c²)
=(3a)²-(b-2c)²
=(3a+b-2c)(3a-b+2c)
(3)x+z=Aとおく
(A+y)(A+3y)-8y²
=A²+4Ay-5y²
=(A-y)(A+5y)
=(x+z-y)(x+z-5y)
(4)a³+b³=(a+b)(a²-ab+b²)をつかう
A³+B³
=(A+B)(A²-AB+B²)
=(x-y+y-z)((x-y)²-(x-y)(y-z)+(y-z)²)
=(x-z)(x²-2xy+y²-xy+xz+y²+yz+y²-2yz+z²)
=(x-z)(x²+3y²+z²-3xy+xz-3yz)