x²-2x≤a²+2a+9(x-1)²-1≤(a+1)²+8(x-1)²≤(a+1)²+9---------------------A已知(a+1)²+9的最小值为（0+1）²+9=10欲x^2-2x≤a^2+2a+9为真命题,需A式左边小于等于右边的最小...