（3/2x的2次方-5xy+y的2次方）-【-3xy+2（1/4x的2次方-xy）+2/3y的2次方】,其中x=1,y=

原式=(3/2x²-5xy+y²)-[-3xy+2(1/4x²-xy)+2/3y²]
=3/2x²-5xy+y²-(-3xy+1/2x²-2xy+2/3y²)
=3/2x²-5xy+y²+3xy-1/2x²+2xy-2/3y²
=(3/2x²-1/2x²)+(-5xy+3xy+2xy)+(y²-2/3y²)
=x²+1/3y²
当x=1,y=-2时：
原式=1²+1/3×(-2)²
=1+4/3
=7/3