(12x^5y⁴z²-6x⁴y³-8x³y²)÷(2xy）×（-4x²y)
=2x³y²(6x²y²z²-3xy-4)÷(2xy）×（-4x²y)
=x²y(6x²y²z²-3xy-4)×（-4x²y)
=-4x⁴y²(6x²y²z²-3xy-4)
=-24x^6y^4z^2+12x^5y^3+16x⁴y²
" ^　''表示几次方