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）

∵ function f (x) = x + lgx-3, (x > 0) ∵ f ′ (x) = 1 + 1xln10, ∵ f ′ (x) > 0, ∵ f (x) is an increasing function, f (2) = 2 + lg2-5 = lg2-3 < 0, f (3) = 3 + lg3-5 = lg3-2 < 0, f (4) = 4 + lg4-5 = lg4-1 < 0, f (5) = 5 + lg5-5 = lg5 > 0, f (4) f (5) < 0

RELATED INFORMATIONS

1. 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]
2. For any x1, X2 (x1 ≠ x2) in the definition field of function f (x) = lgx, the following conclusion is obtained f(（x1+x2）/2)
3. 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]
4. 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]
5. 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,
6. 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"
7. 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
8. 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——————
9. If the function f (x) = x ^ 2-3x-k has zeros on (- 1, 1), then the value range of K
10. 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
11. The interval where the zeros of the function f (x) = - (1 / x) + lgx lie is
12. 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）
13. Try to find an interval of length one where the function y = (x-1) \ (3x + 2) has at least one zero point
14. The interval where the zeros of the function f (x) = 2x + 3x lie is______ ．
15. Find the zero point of function y = (3x ^ 2-x ^ 2) / (x ^ 2-1) + 1 / (1-x) - 2
16. The number of zeros of function y = x ^ 2-3x + 1
17. Finding the zeros of the function y = (3x-x ^ 2) / (x ^ 2-1) + 1 / (1-x) - 2
18. The zero point of the function f (x) = x2-3x + 2 is () A. （1，0），（2，0）B. （0，1），（0，2）C. 1，2D. -1，-2
19. The even function f (x) defined on R satisfies that for any x1, X2 belongs to (negative infinity, 0) (x1 ≠ x2), and (x2-x1) (f (x2) - f (x1)) > 0, then when n belongs to N +, f（n+1）
20. Even functions defined on R satisfy the following conditions: for any X &;, X &; ∈ [0, + ∞], there is f (x1) - f (x2) / x1-x2 ＜ 0 The size order of F (3), f (- 2), f (1) (solving process)