1/2x-2(x-1/3y的平方)+(3/2+1/3y的平方)=1/2x-2x+2/3y的平方+3/2+1/3y的平方=-3/2x+y²+3/2 x=-2 y=-0.5-3/2x+y²+3/2=3+0.25+1.5=4.75
