Let x0 be the solution of the equation LNX + x = 4, then x0 belongs to the interval () A. （0，1）B. （1，2）C. （2，3）D. （3，4）

Let x0 be the solution of the equation LNX + x = 4, then x0 belongs to the interval () A. （0，1）B. （1，2）C. （2，3）D. （3，4）

From LNX + x = 4, we can get: LNX = 4-x. draw the corresponding function image on both sides of the equation: LNX = 4-x, as shown in the figure. From the figure, we can see that their intersection x0 is in the interval (2, 3), so we choose C

If the price of a commodity is 486 yuan after two successive price reductions of 10%, the price before the price reduction is 486 yuan______ Yuan

Suppose that the price before the price reduction is x yuan. From the meaning of the question, we get x × (1-10%) 2 = 486, and the solution is x = 600

Let x0 be the solution of the equation LNX + x = 4, then x0 is in the following interval ()
A. （3，4）B. （0，1）C. （1，2）D. （2，3）

If f (x) = LNX + x-4, then the domain of definition of F (x) is (0, + ∞), and the function increases monotonically, ∵ f (2) = LN2 + 2-4 = ln2-2 < 0, f (3) = Ln3 + 3-4 = ln3-1 > 0, and the interval of zeros of ∵ f (x) = LNX + x-4 is (2,3), that is, the solution of equation x0 is (2,3)

If the price of a commodity is reduced by 20% each time for two consecutive times, the original price is m yuan

m/(1-20%)/(1-20%)=25m/16

If the solution of LNX + 3x-6 = 0 is a, then the minimum integer solution of X ≥ A is?

It's better to combine numbers with figures
lnx 6-3x
x=1 0 3
x=2 0

A tape recorder, the original price of 100 yuan, after a discount price of 1 / 5, how much is the current price of this tape recorder

100 times four fifths = 80

Solution equation: (x-1) × 22 = (x-3) × 26
（x-1）×22=（x-3）×26
(writing process)

Solution
(x-1)×22=(x-3)×26
22x-22=26x-78
22x-26x=22-78
-4x=-56
x=14

The current price of a tape recorder is 420 yuan, one seventh lower than the original price. How much is the original price of this tape recorder?

420 (1-1 / 7) = 490 (yuan)
A: the original price of this recorder is 490 yuan

Solution equation: (22-x) * 1 / 4-1 / 5 x = 1

(22-x) * 1 / 4-1 / 5 x = 1
22/4-x/4-x/5=1
22/4-9x/20=1
18/4=9x/20
x=10

The price of a tape recorder is reduced by 20% and then by 20%. After two price reductions, the price is 128 yuan. What is the original price of this tape recorder

Let the original price of the recorder be x yuan
x（1-0.2）^2=128
The solution is x = 200
A: the original price of this tape recorder is 200 yuan