(2x的平方+ax-y+6)-(2bx的平方-3x+5y-1)=(2-2b)x²+(a+3)x-5y+7 2-2b=0b=1a+3=0a=-3 1/2a²-2b²+4ab=1/2x(-3)²-2x1²-4x3x1=9/4-2-12=-11又3/4