A square table consists of a table top and four legs. It is known that one cubic meter of wood can be used for 50 tables or 300 legs (equations only) A square table consists of a table top and four legs. It is known that one cubic meter of wood can make 50 tables or 300 legs. Please help the carpenter to calculate how many square tables can be made with five cubic meters of wood The equation can be set up linear equation in two unknowns

A square table consists of a table top and four legs. It is known that one cubic meter of wood can be used for 50 tables or 300 legs (equations only) A square table consists of a table top and four legs. It is known that one cubic meter of wood can make 50 tables or 300 legs. Please help the carpenter to calculate how many square tables can be made with five cubic meters of wood The equation can be set up linear equation in two unknowns

One cubic meter of wood can be used for 50 tabletops or 300 legs
A table needs 1 / 50 cubic meter of wood,
A table leg needs 1 / 300 cubic meter of wood
If you need x desktops, you need 4x legs
So:
x/50+(4x)/300=5.
So: x = 150
So you can make 150

After cutting a section of cylindrical wood into a largest cone, the volume is reduced by 18.84 cubic decimeters. It is known that the height of the wood is 3 decimeters, and the bottom area of the wood is calculated

When a section of cylindrical wood is cut into a maximum cone, the volume is reduced by 18.84 cubic decimeters. Therefore, the volume of the wood is 18.84x2/3 = 28.26dm3. (when a section of cylindrical wood is cut into a maximum cone, the volume is reduced by 2 / 3), and the bottom area is 28.26/3 = 9.42dm2

A section of cuboid wood is 1.2 meters long. If you want to cut it short by 2 cm, its volume will be reduced by 40 cubic cm

1.2 m = 120 cm, 40 △ 2 × 120 = 20 × 120 = 2400 (cubic cm); a: the original volume of this section of wood is 2400 cubic cm

A section of cuboid wood is 1.2 meters long. If you want to cut it short by 2 cm, its volume will be reduced by 40 cubic cm

1.2 m = 120 cm, 40 △ 2 × 120 = 20 × 120 = 2400 (cubic cm); a: the original volume of this section of wood is 2400 cubic cm

1. The distance between the two docks is 120km. The average speed of the cruise ship is 30km per hour from place a to place B, and the average speed of the cargo ship is 40km per hour from place B to place a
2. For a bundle of cables, 40% of the total length was used for the first time, 140m was used for the second time, and the ratio of the remaining one to the used one was 1:3. How many meters was the original bundle of cables?
3. A pile of chessmen, the sunspots are three times as many as the white ones. Each time there are five sunspots and two white ones. After several times, the white ones have finished, and there are still 11 sunspots left. How many white ones are there in this pile of chessmen?
4. The number of students in class 51 is equal to that in class 52. The number of boys in class 51 is 20% less than that of girls in class 52. The ratio of boys in class 52 to girls in class 51 is 5:7. There are 30 girls in class 52. How many students are there in these two classes?

1.
First calculate the time from a to B 120 / 30 = 4 hours
Then calculate the time from B to a 120 / 40 = 3 hours
So 3 + 4 = 7 hours
(30 + 40) / 7 = 10km / h

1. If log2 (- x) < x + 1 holds, what is the value range of X?
2. If the function loga (1-ax) increases monotonically on [2,3], then the value range of a is?

1. 2^(x+1)>-x
From the image of F (x) = 2 ^ (x + 1) g (x) = - x, where f (x) is above g (x), the interval of x-axis is the solution`
So we need X

The application of derivative function
Finding the tangent slope of parabola y = x ＾ 2 passing through point (1,1)

Set tangent point P (x0, x0 ^ 2)
y'=2x
Put P in
The tangent slope is 2x0
Again (1,1)
The tangent equation is Y-1 = 2x0 (x-1)
The tangent equation also passes through point P
The P point is substituted into x0 ^ 2-1 = 2x0 (x0-1), and x0 = 1 is obtained
The tangent slope is 2

If and only if vectors a (x1, Y1) and B (X2, Y2) are parallel?
Vector, parallel, necessary and sufficient condition

Vector a = (x1, Y1), vector b = (X2, Y2), the necessary and sufficient condition of parallel is x1y2-x2y1 = 0

It is proved that x Λ 2 + y Λ 2 + XY ≥ 3 / 4 (x Λ 2 + y Λ 2) (if x + y + Z = 1)

Is the condition wrong? Is it x + y = 1?

Who has the problem of adding and subtracting three numbers within 100
For example, 30 + 20-50, the more the better

25+35-14
80-64+25
14+38+15
39+7-40
13+58-62
10-5+46
14+69-52
19+25-63
14-5+96