∵y分之x=七分之二
y=7x/2
2(x的2次方)-3xy+7(y的2次方)分之(x的2次方)-3xy+2(y的2次方)
=(x²-21x²/2+49y²/2)/(2x²-21x²/2+343x²/4)
=15x²/(309x²/4)
=60/309
=20/103
∵y分之x=七分之二
y=7x/2
2(x的2次方)-3xy+7(y的2次方)分之(x的2次方)-3xy+2(y的2次方)
=(x²-21x²/2+49y²/2)/(2x²-21x²/2+343x²/4)
=15x²/(309x²/4)
=60/309
=20/103