(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy²）,其中x=-1,y=2.先化简,后求值,

(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy²）,其中x=-1,y=2.先化简,后求值,
(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy²）,其中x=-1,y=2.
先化简,后求值,

(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy²）,其中x=-1,y=2.先化简,后求值,
(2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy²）
=2x²y-3xy²-3x²y+6xy²+2x²y-8xy²
=x²y-5xy²
=xy(x-5y)
将x=-1,y=2.代入得
原式=-2×(-1-10)=22