For any x1, X2 (x1 ≠ x2) in the domain of function f (x), the following conclusions are obtained: (1) f (x1 + x2) = f (x1) + F (x2); (2)f(x1·x2)=f(x1)+f(x2); (3)[f(x1)-f(x2)]/(x1-x2)>0; (4)f[(x1+x2)/2]

1.kx
2.lnx
3、x
4.x^2

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1. For any x1, X2 (x1 ≠ x2) in the domain of definition of function f (x), we have the following conclusion: (1) f (x1 + x2) = f (x1) * f (x2) (2) f (x1 * x2) = f (x1) + F (x) (1)f(x1+x2)=f(x1)*f(x2) (2)f(x1*x2)=f(x1)+f(x2) (3)[f(x1)-f(x2)]/(x1-x2)>0 (4) f[(x1+x2)/2]
2. For the function f (x) = 1 / X (x > 0) in the domain x1, X2 (x1 ≠ x2), we have the following conclusions 1.f（x1+x2)=f（x1）+f（x2）；2.f（x1x2）=f（x1）f（x2）；3.f(x1)-f(x2) / x1-x2; 4.f(x1+x2 / 2)＜f(x1)+f(x2) / 2 The correct conclusion in the above conclusion is -- () the answers are 2 and 4, but I don't know why 4 is right,
3. Let y = log2 ^ (0, + ∞). If f (x) = lgx, try to judge 1 / 2 "f (x1) + F (x2) and 1 / 2" f (x1) + F (x2) according to the image of F (x) F "((x1) + (x2)) / 2"
4. It is known that the zeros of the function y = x ^ 2 + 2mx + 2m + 3 (M belongs to R) are x1, x2, Find the minimum value of X1 ^ 2 + x2 ^ 2
5. If M belongs to R X1 and X2 are two zeros of the square of the function f (x) = x-2mx + 1-m, then the minimum value of the square of X1 plus the square of X2 is——————
6. If the function f (x) = x ^ 2-3x-k has zeros on (- 1, 1), then the value range of K
7. If f (x) = x ^ 2-2 / 3x-k has zero on [- 1,1], then the value range of real number k I want a detailed process... Don't just give me an answer
8. If f (x) = x ^ 3 + ax ^ 2 + BX + 27 has a maximum at x = 1 and a minimum at x = 3, then a-b=
9. Given the function y = ax ^ 3 + BX ^ 2, when x = 1, there is a maximum of 3. Find (1) the analytic expression of the function and write his monotone interval (2) to find the maximum and minimum of the function on [- 2,1]
10. Given the real number a ≠ 0, the function f (x) = ax (X-2) ^ 2 (x belongs to R) (1). If the function f (x) has the maximum value 32 | 27, find the value of A (2) If the inequality f (x) < 32 holds for any x, the value range of a is obtained
11. For any x1, X2 (x1 ≠ x2) in the definition field of function f (x) = lgx, the following conclusion is obtained f(（x1+x2）/2)
12. X 2 ∈ (0. + ∞), if f (x) = lgx, compare the sizes of [f (x 1) + F (x 2)] / 2 and f [(x 1 + x 2) / 2]
13. The interval of zero point of function f (x) = lgx + X-5 is () A. （1，2）B. （2，3）C. （3，4）D. （4，5）
14. The interval where the zeros of the function f (x) = - (1 / x) + lgx lie is
15. The interval where the zeros of the function f (x) = - 1x + lgx are located is () A. （0，1）B. （1，2）C. （2，3）D. （3，10）
16. Try to find an interval of length one where the function y = (x-1) \ (3x + 2) has at least one zero point
17. The interval where the zeros of the function f (x) = 2x + 3x lie is______ ．
18. Find the zero point of function y = (3x ^ 2-x ^ 2) / (x ^ 2-1) + 1 / (1-x) - 2
19. The number of zeros of function y = x ^ 2-3x + 1
20. Finding the zeros of the function y = (3x-x ^ 2) / (x ^ 2-1) + 1 / (1-x) - 2