(-3xy的2次方)×(2-3x-4x的2次方y)

问题描述:

(-3xy的2次方)×(2-3x-4x的2次方y)

=(-3xy²)×2-(-3xy²)×3x-(-3xy²)×4x²y
=-6xy²+9x²y²+12x³y³