1 1.？ The table on the right is the record of A and B throwing basketball in the game.

Hit ratio (ratio of shooting times to pitching times)

To compare the performance of pitching, if their performance

Just as good. The following relationships exist:

j？ a-b = 5； ? k？ a+b = 18； ? l？ a:b = 2: 1； ? m？ a: 18 = 2:3；

Which one is correct? (Fill in serial number only).

12.？ Suppose the solution of the equation is 0, and point A(m, n) is on the image of inverse proportional function y=, then the value of k

what's up .

13.？ What is the ratio of the degrees of the two internal angles of an isosceles triangle? (a<b), if this triangle is an obtuse triangle, the value of.

What is the scope? .

14.？ Define f? (x)=？ (x？ 1), then =? .

15.？ The images of function y=ax and function y=x+b are shown in fig. 5, so x, y

What is the solution of the equation? .

16.？ If a and b are natural numbers and a >；; B, 2011= a (a-1)+B. So a=? ; b=？ .

17.？ A dice, the numbers on six faces are 1, 2, 3, 4, 5, 6. Roll the dice twice, and the number on it depends on it.

If the suffix is m, n, what is the probability that the equations of x and y have solutions? .

18.？ As shown in Figure 6, there is a small P in the square ABCD with a side length of 2+, and? PAB=30，PA=2，

There is a point q on the side of the square ABCD, and △PAQ is an isosceles triangle, which satisfies the conditions.

What is point q? Answer.

19.？ It is known that a, b and c are real numbers. For any real number x, there is always? |? x+a？ |+|? 2x+b？ |=|? 3x+c？ |,

So a: b: c = .

20.？ A bicycle tire, if mounted on the front wheel, will be scrapped after driving for 5000 kilometers; If installed on the rear wheel, travel 3000 miles.

Scrapped after one kilometer. There is a new bike. After driving for a certain distance, exchange the front and rear tires and continue driving.

So two tires are scrapped at the same time, which car runs at most? kilometre (km)