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The first volume of junior high school mathematics homework A14 page answer to be fast ah high score
1. Rational number: ① ③ ⑤ ⑥ ⑦ Ⅷ; irrational number: ② ④ 2 (1) radical five, radical five (2) π, - π (3) ± radical three 3 D 4. Draw the graph by yourself, - 1.5 (there is a point on 5) ＜ - radical two ＜ 0 ＜ 1 / 2 ＜ π - 25 ① 6 is between 6 and 7. ①∵ 12 = 1 22 = 4 32 = 9 42 = 1
It is known that the total amount of the first donation is 4800 yuan, and the total amount of the second donation is 5000 yuan. The number of the second donation is 20 more than that of the first donation, and the per capita donation of the two times is exactly the same. If the number of the first donation is x, then the number of the second donation is () and the first donation can be expressed as 4800 / X Yuan by the algebraic formula of X, The second contribution per capita can be expressed as () yuan by the algebraic formula of X. according to the equality of the two contributions per capita, the equation () can be listed
2. Change the formula u = IR into the form of u, R and I, then I = ()
3. Change the formula s = π Rl (R is not equal to 0) into the known form of S, R, finding L, then l = ()
4. Change the formula s = V0 + at (a is not equal to 0) into the form of V, V0, a and t
5. A store sells a batch of clothes, each of which costs 150 yuan, making a profit of 25%
The number of the second donation is x + 20
The second contribution per capita can be expressed as 5000 / (x + 20) yuan by the algebraic formula of X
The equation 4800 / x = 5000 / (x + 20) can be listed
l=U/R
l=S/πr
t=(S-v0)/a
150 / (1 + 25%) = 150 / 1.25 = 120 yuan
Ask the fifth chapter review question answer, have a picture, oneself see SA!
If not, how to correct it?
The solution equation is: 2 (x + 3) - 5 (1-x) = 3 (x-1),
If we remove the brackets, we get 2x + 3-5-5x = 3x-3,
If we transfer the term, we get 2x-5x-3x = - 3 + 5-3,
It is reduced to - 6x = - 1
x=1/6
3-（5-2x）=x+2 （x+2）/2-（2x+3）/3=1
There are two engineering teams, team a and team B. team a has 54 members and team B has 48 members. To make the number of team a twice that of team B, how many members should be transferred from team B to team a
Xiaoming and Xiaohua are walking at the same time from two places 44 kilometers away. Xiaoming's speed is 5 km / h and Xiaohua's speed is 6 km / h
How many kilometers did Xiao Hua walk when he met
How many kilometers is the distance between Xiaoming and Xiaohua after 2 hours
Dad took 30 kilograms of luggage and bought a 165 yuan luggage ticket
Passengers can carry 20 kg of luggage free of charge, and 1.5% of the ticket price for the overweight part
Dad flies from Hangzhou to Beijing. Can you work out the price of dad's ticket
A class of students organized a clean-up, 21 people went to the library, 12 people went to the laboratory, and another 15 people were waiting in the classroom for allocation. The monitor wanted to make the number of people going to the library exactly double the number of people going to the laboratory
If all the students waiting in the classroom are transferred to the library and laboratory, how many people should be transferred to the library
If four of the students waiting in the classroom are sent to clean the teacher's office first, and then all the remaining students are transferred to the library and laboratory, can the deployment be carried out according to the requirements, and the number of students transferred to the library can be calculated; if not, reason
The solution equation is: 2 (x + 3) - 5 (1-x) = 3 (x-1),
Remove the brackets and get 2x + 6-5 + 5x = 3x-3,
Move the term, get 2x + 5x-3x = - 3 + 5
If we simplify it, we get 4x = 2
x=1/2
Well The problem is very simple. Let's start with the equations
1｛X+Y=7 、X+Y+Z=5、X-y-z=1
2｛5x+6y+2z=80、4x-3y+z=16、3x-2y+6z=92
Answer within half an hour,
1. X + y = 7 (1) x + y + Z = 5 (2) X-Y-Z = 1 (3) (2) - (1), z = - 2, substituting z = - 2 into (2), x + Y-2 = 5 (4) into (3), X-Y + 2 = 1 (5) (4) + (5), 2x = 6, x = 3, substituting x = 3 into (1), 3 + y = 7, y = 4, so the solution of the original equations is x = 3, y = 4, z = - 22.5x + 6y + 2Z = 80 (1) 4x-3y + Z = 1
Given that ABC is the unit vector, 3A + XB + 7C = 0, and the angle between a and B is 60 degrees, what is the real number x equal to
a. B and C are unit vectors. The angle between a and B is 60 degrees,
∴a*b=1/2,
3a+xb+7c=0,
∴3a+xb=-7c,
Square 9 + x ^ 2 + 3x = 49,
x^2+3x-40=0,
∴x1=5,x2=-8.
Take 20 examples of sublimation in life
1. Frost; 2. Tree hanging (RIME); 3. Window decoration; 4. Iodine vapor becomes solid iodine when it is cold; 5. Frost is often hung on outdoor objects on cold winter mornings, and frost is a small ice particle formed by direct condensation of water vapor in the air; 6. Ice flower appears on glass in cold winter mornings; long used bulb wall turns black; 5;
5x + 2 (15-x) = 90
5X+2（15-X）=90
5x+30-2x=90
5x-2x=90-30
3x=60
x=20
Solving fractional equation: (1 / x-3) - (6 / x ^ 2-9) - (x-1 / 6-2x) = 1 / 2
From the meaning of the title, we can see that x ≠ 3 and X ≠ - 3
The original equation can be reduced to: 1 / (x-3) - 6 / (X & # 178; - 9) + (x-1) / [2 (x-3)] = 1 / 2
Then the two sides of the original equation are multiplied by 2 (X & # 178; - 9) to obtain:
2(x+3) - 12 +(x-1)(x+3)=x²-9
2x+6-12+x²+2x-3=x²-9
4x=0
The solution is: x = 0
It is proved that x = 0 satisfies the original equation
So the solution of the original equation is: x = 0
Calculate with a calculator
4 times root 11, 5 times root 10.34, - 6 times root (- 0.1), 5 times root - 1.567 * 10, 6 times root 3, 4 times root 9, 6 times root 27, 8 times root 81, 10 times root 243
Get to the thousandth
The root of 4 times is 11 = 1.821
5 times root 10.34 = 1 / 600
-Four times of the sixth root sign (- 0.1) (the meaning of the first negative sign is not clear)
6 times of 5 times root - 1.567 * 10 = 17.3386
Root 3 = 1.7321
4 times root 9 = 1.7321
6 times root 27 = 1.7321
8 times root 81 = 1.7321
10 times root 243 = 1.7321
4.8 △ 8 + 5.2 × 8 / 1 (2 / 1-3 / 1 × 75%) divided by 0.25
4.8 △ 8 + 5.2 × 1 / 8
=4.8x1/8+5.2x1/8
=(4.8+5.2)x1/8
=10x1/8
=5/4
(1 / 2-1 / 3 × 75%) except 0.25
=(1/2-1/3x3/4)x4
=(1/2-1/4)x4
=1/4x4
=1
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