23*14/39+14*16/39 Simple calculation

23*14/39+14*16/39 Simple calculation

nine point one three zero eight three four nine seven six nine eight eight eight two three

How much is 23 × 14 out of 39 plus 14 times 16 out of 39

I will

On the application of quadratic equation of one variable
When a farmer grows peanuts, the yield of the old varieties is 2000 kg / ha, and the oil yield is 50% (that is, 50 kg of peanut oil can be processed for every 100 kg of peanut). After planting new varieties of peanuts, the peanut harvested per ha can be processed into 1320 kg of peanut oil, of which the growth rate of peanut oil yield is half of the yield per ha?

Suppose the growth rate of peanut per hectare is x, then the growth rate of peanut oil yield is 50% X
2000（1+x)×[50%×(1+50%x)]=1320
2000 (1 + x) this is the yield per hectare of the new peanut variety
50% × (1 + 50% x) this is the new oil yield
The original equation is simplified step by step
（2000+2000x）(0.5+0.25x)=1320
500x^2+1500x+1000=1320
500x^2+1500x-320=0
50x^2+150x-32=0
50(x+1.5)^2-112.5-32=0
50(x+1.5)^2=144.5
(x+1.5)^2=289/100
X + 1.5 = 17 / 10 or x + 1.5 = - 17 / 10
According to the actual situation, X is greater than 0, so x + 1.5 = 17 / 10, x = 0.2 = 20%
A: the growth rate of new peanut varieties is 20% per hectare

Applied problems of quadratic equation with one variable in junior high school mathematics
It is known that the time required for team a to complete the project alone is more than 4 days, and the time required for team B to complete the project alone is 16 days less than 2 times of the specified time. If the cooperation between team a and team B takes 24 days to complete, can the cooperation between team a and team B be completed within the specified time?

Set the time to X days
1/(2x+4)+1/(2x-16)=1/24
12(x-8)+12(x+2)=(x+2)(x-8)
x²+2x-8x-16-12x+96-12x-24=0
x²-30x+56=0
X = 2 (rounding off) or x = 28
The cooperation between Party A and Party B can be completed within the specified time

When someone walks along the tram route, a tram will catch up with him every 12 minutes, and a tram will come face to face every 4 minutes. If both the pedestrian and the tram are moving at a constant speed, the tram will leave the starting station every few minutes?

Suppose the speed of the tram is a and the speed of the people is B, and the car leaves every X minutes
The two cases were analyzed separately
1. First analyze the car in the same direction, and use 12 minutes to catch up with ax
(a-b)*12=ax
2. In the same way, for opposite cars, people and cars use 4 minutes to complete the distance of ax together, and the
(a+b)*4=ax
It can be concluded from formula 1.2
24a=4ax
So x = 6, that is, every six minutes

Junior high school mathematics calculation problem solving (2 / √ 3-1) + 2cos60 ° + √ (3 + π) &# 178; + half of the negative power
The front one is the root sign three minus two-thirds, not √ (3-1)

Original formula = radical 3 + 1 + 1 + 3 + π + 2 = 7 + π + radical 3

At present, 600 telephones in the telecommunications bureau have applied for telephone installation. In addition, there are new telephone applications to be installed in media day. Assuming that the number of new telephone applications is the same every day, if three installation teams are arranged, the installation can be completed in 60 days. If five installation teams are arranged, the installation can be completed in 20 days. How many telephones are newly applied in each day? How many telephones are installed in each installation team every day?

X units are installed every day and Y units are added every day
600+60y=3×60x
600+20y=5×20x
∴x=10
y=20
Each group is equipped with 10 machines per day and 20 new machines per day

A very simple junior high school mathematics problem
A small ball starts to roll down the slope from rest, and its rolling speed increases by 2m / s per second
1. Find the functional relationship between the ball speed V (unit: M / s) and the rolling time t (unit: s)
2. Find the speed of the ball when rolling 3:5s!

Simple physical problems:
Acceleration a = 2m / S
1. Function relation
The velocity is v = a * t = 2T
2. The speed of the ball
When t = 3.5s, v = 2 * 3.5 = 7m / s

(- a-b) & sup2; =? Why

Square formula
a²+2ab+b²

If the rational numbers x, y and Z satisfy the square of | X-1 | + | y + 2 | + (2z-1) = 0, find the value of (XYZ) 2004 △ (the 13th power of X * y and the 12th power of Z) (the answer is negative half,
The result is minus one in two

Because the rational numbers x, y, Z satisfy the square of | X-1 | + | y + 2 | + (2z-1) = 0, so the squares of | X-1 |, | y + 2 |, (2z-1) are zero, respectively. So x = 1, y = - 2, z = 1 / 2 will bring x, y, Z into (XYZ) 2004 △ (the 13th power of X * y * the 12th power of Z), that is 1 / (- 2's 13th power) * (1 / 2's 12th power)