设涨价x元,则售价是50+x元一个得利润是50+x-40=x+10元销量减少10x个,是500-10x所以利润=(x+10)(500-10x)=8000-10x²+400x+5000=8000x²-40x+300=0(x-10)(x-30)=0x=10,x=3050+x=60,或80所以售价是60元或80元...