把下列格式分解公因式 7x²-63 a³-a 3a²-3b² y²-9(x+y)²
问题描述:
把下列格式分解公因式 7x²-63 a³-a 3a²-3b² y²-9(x+y)²
答
7(x+3)(x-3) a(a+1)(a-1) 3(a+b)(a-b) (3x+4y)(-3x-2y)
答
7x²-63
=7(x²-9)
=7(x-3)(x+3)
a³-a
=a(a²-1)
=a(a+1)(a-1)
3a²-3b²
=3(a²-b²)
=3(a-b)(a+b)
y²-9(x+y)²
=(y-3(x+y))(y+3(x+y))
=(-3x-2y)(3x+4y)