x^2 + bx + c = 0
delta = b^2 - 4c >= 0
b >= 2根号c
b=6,5,4,3,2,c=1 5/6 *1/6 = 5/36
b=6,5,4,3,c=2 4/6*1/6 = 4/36
b=6,5,4,c=3 3/6*1/6 = 3/36
b=6,5,4 c=4 3/6*1/6 = 3/36
b=6,5,c=5 2/6*1/6 = 2/36
b=6,5,c=6 2/6*1/6 =2 /36
方程x的平方加上bx加上c有实数根的概率为 加起来一共是 19 / 36