When A=0, b can choose one of the three numbers as c (2,3) = 3.

When B=0, a can take any one of 1, 2, 3 (except for the case of all zeros, which is already included above, there are three cases.

B takes 1, and A can take 1, 2, 3, three cases (excluding the case that A is equal to zero).

B takes 2, A can only take 2, 3, two cases (excluding the case that A equals zero),

So * * * has a real root in 3+3+3+2= 1 1.

* * * The total number of combinations is 4*3= 12, and the probability of having real roots is1112 = 91%.

Two questions,

The inequality above becomes:? A & gt=B, A=B is a straight line. According to the value interval, the probability of all values is within the rectangle with an area of 6, because B=2? A=2, which means that any number of A>2 satisfies the condition, and the condition without real roots is A.

So the probability of having real roots is = 1-2/6~=66.7%.