Exercises of inequality in grade one of junior high school

Exercises of inequality in grade one of junior high school

The following formulas are: ① 3x = 5; ② a > 2; ③ 3m-1 ≤ 4; ④ 5x + 6y; ⑤ a + 2 ≠ A-2; ⑥ - 1 > 2. There are () a, 2b, 3C, 4D and 52 inequalities

Inequality exercises in grade one of junior high school
1. When setting off fireworks, for the sake of safety, people should move to a place more than 10 m after lighting the fuse. The known burning speed is 0.002 M / s, and the person's leaving speed is 4 m / s. what conditions should the length a (m) of the fuse meet?
2. Compare the size of 5A and 4a. Xiaoming said: "5A > 4a." Xiaojun said: "impossible". Which viewpoint is right? Why?
3. A worker plans to process 408 parts in 15 days. In the first three days, 24 parts are processed every day. How many parts can be processed at least in the future to complete the task within the specified time?
4. It takes an hour for the ambulance to deliver the medicine to the place 120km away. It has already walked 50km in the first half hour. At least how fast can the ambulance go in the second half hour to deliver the medicine in time?

1. When setting off fireworks, for the sake of safety, people should move to a place more than 10 m after lighting the fuse. The known burning speed is 0.002 M / s, and the person's leaving speed is 4 m / s. what conditions should the length a (m) of the fuse meet?
(a/0.002)*4>10
a>10*0.002/4
a>0.005
The length of fuse a (m) should be greater than 0.005 M
2. Compare the size of 5A and 4a. Xiaoming said: "5A > 4a." Xiaojun said: "impossible". Which viewpoint is right? Why?
Neither view is right!
When a is less than or equal to 0, 5A > 4A does not hold, so Xiao Ming's view is wrong!
When a is greater than 0, 5A > 4A holds, so Xiaojun's view is not correct!
When a is less than 0, 5a4a
3. A worker plans to process 408 parts in 15 days. In the first three days, 24 parts are processed every day. How many parts can be processed at least in the future to complete the task within the specified time?
After the design, the average daily processing X
(408-24*3)/X=120
X/2>=70
X>=140
In the second half of an hour, at least 140km / h, it can be transported in time

If the maximum value of function f (x) = logax (a > 1) in the interval [a, 2A] is three times the minimum value, then the value of a is ()
A. 2B. 3C. 2D. 3

∵ a > 1 ∵ the function f (x) = logax increases monotonically in the interval [a, 2A]; when x = a, the function f (x) takes the minimum value 1; when x = 2A, the function f (x) takes the maximum value 1 + loga2 ∵ the maximum value of the function f (x) = logax in the interval [a, 2A] is three times of the minimum value, ∵ 1 + loga2 = 3, that is, loga2 = 2, the solution is a = 2, so a is selected

The propagation speed of radio wave is the same as the speed of light. The radio wave receives the reflected wave after 2.56s, so the distance between earth and moon is about______ km

38400km

If the square of the quadratic function FX = ax + BX + C (a is not equal to 0), the partial corresponding values are shown in the following table: find the inequality FX

According to the meaning of the problem, the opening of quadratic function image is upward,
And f (- 2) = f (3) = 0
Therefore, the solution of the inequality f (x) < 0 is
-2＜x＜3

If the distance between two corresponding points of two numbers with equal absolute value on the number axis is 6, then the two numbers are ()
A. + 6 and - 6B. + 3 and - 3C. + 6 and - 3D. + 3 and + 6

According to the meaning of the question, these two numbers are opposite to each other, because the distance between the two points corresponding to the two numbers on the number axis is 6, so the two numbers are ± 3

If f (x) is a decreasing function on (0, + ∞), then the relationship between F (a2-a + 1) and f (3 / 4) is positive
Why a2-a + 1 = (a - 1 / 2) 2 + 3 / 4 ≥ 3 / 4,
This is a decreasing function, isn't f (a2-a + 1) not equal to f (3 / 4)?

a2-a+1
Can be formulated
Become (A-1 / 2) ^ 2 + 3 / 4
The square is greater than or equal to 0
So a ^ 2-A + 1 is bigger than 3 / 4
So the value of the function decreases as x increases
So f (a ^ 2-A + 1)

Please write three similar terms of - 3x3yz & # arbitrarily

2x³yz²,7x³yz²,5x³yz²

Let f (x) = LNX, the inverse function of G (x) = 2 (x + 1) / (x-1), then f (g (x))

y=g^-1(x)=2(x+1)/(x-1)
x(y-2)=y+2
x=(y+2)/(y-2)
XY interchange
g(x)=(x+2)/(x-2)
f(g(x))=ln(x+2)/(x-2)
x> 2 or X

Given function f (x) = e ^ X-1, G (x) = ln (x + 1)
Given the function f (x) = e ^ X-1, G (x) = ln (x 1) 1) find the common tangent at the intersection of two curves 2) find the minimum value of function f (x) = | f (x) | - G (x) 2) given 0 ≤ y < x, try to compare the size of F (X-Y) and G (x) - G (y) and prove the conclusion

If f (x) - G (x) is derived, e ^ x + 1 / (x + 1) is simple increasing in the effective value range of X. therefore, f (x) and G (x) have and only have one intersection point. If the solution is (0,0), and the slope of the line is 1, then the common tangent is y = X. as mentioned above, from 0 to positive infinity, f (x) is simple increasing, and the minimum value is 0; from - 1 to 0, f (x) is not negative, so f (x)