1 （-6x+y)(-6x-y)
=(-6x(²-y²
=36x²-y²
2 （-6x+y)(6x-y)
=-(6x-y)²
=-(36x²-12xy+y²)
=-36x²+12xy-y²
3（-6x+y)(x-6y)
=-6x²+36xy+xy-6y²
=-6x²+37xy-6y²