(-x-2y)(x-2y)+(-x-3y)²
=-(x+2y)(x-2y)+[-(x+3y)]²
=-(x²+4xy+4y²)+(x²+6xy+9y²)
=-x²-4xy-4y²+x²+6xy+9y²
=2xy+5y²
=2×4分之1×(-1)+5×(-1)²
=-2分之1+5
=2分之9
(-x-2y)(x-2y)+(-x-3y)²
=-(x+2y)(x-2y)+[-(x+3y)]²
=-(x²+4xy+4y²)+(x²+6xy+9y²)
=-x²-4xy-4y²+x²+6xy+9y²
=2xy+5y²
=2×4分之1×(-1)+5×(-1)²
=-2分之1+5
=2分之9