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3(x-3)=5-2(2-5x)； 2（4x-3）-5=6（3x-2）-2（x+1）
3(x-3)=5-2(2-5x)
3x-9=5-4+10x
10x-3x=-9-1
7x=-10
x=-10/7
2（4x-3）-5=6（3x-2）-2（x+1）
8x-6-5=18x-12-2x-2
8x-11=16x-14
16x-8x=-11+14
8x=3
x=3/8
A total of 402 teachers and students rent cars for spring outings. There are two kinds of cars available. The big car can seat 48 people, and each car costs 300 yuan. The small car can seat 30 people, and each car costs 240 yuan. How many big cars and small cars do you need to rent to make the teachers and students just full?
Note: equations cannot be used,
However, can you provide the formula?
The multiples of 48 and 30 within 402 are as follows:
Multiple of 48: 48,96144192240288336384
Multiple of 30: 30,60,90120150180210240270300330360390
If you rent a car, the number of people on the bus must be a multiple of 10. Because the mantissa of 402 is 2, the total number of people on the bus is 2. If you look at the multiple of 48, it must be 192 people, so the rest will take 210 people by car. It's cheap to take a car, ha ha!
Finally, we can know 4 big cars and 7 small cars
Hope to be able to teach!
(1) if A3 × A4 × A5 = 8, find the value of A6. (2) if A1 × A9 = 64, A3 + A7 = 20, find the value of a11
A 3 × a 4 × a 5 = (a 4 / Q) × a 4 × a 4q = a 4 & # 179; = 8 a 4 = 2 a 6 can not be obtained. A 4. A 1 × a 9 = 64 > 0, a 1 and a 9 have the same sign, and a 3 + a 7 = 20 > 0. The odd number terms of the sequence are all positive. A 1 × a 9 = a 1 & # 178; Q ^ 8 = (a 1q & # 8308;) &# 178; = a 5 & # 178; = 64 a 5 = 8 a 3 + a 7 =
(1)aq^3=2
a=2/q^3
a2*a6=4
a2=2a6^(1/2)
a6=16^(1/3)
5x-3=x^2
Quadratic equation of one variable
5x-3=x^2
a=-1 b=5 c=-3
b^2-4ab=25-12
=13
x=5±√13/2
x1=5+√13/2
x2=5-√13/2
X ^ 2-5x + 3 = 0
X=[-b±√（b^2-4ac）]/2a
=[5±√13]/2.
A train has 16 carriages, each of which is 30 meters long, with an interval of 4 meters between two adjacent carriages. It takes 4 minutes for the train to drill through four consecutive caves. It is known that each cave is 750 meters long, and the distance between two adjacent caves is about 440 meters. The train travels () meters per minute
Train length: 16 × 30 + (16-1) × 4 = 540M
Total distance of Cave: 750 × 4 + (4-1) × 440 = 4320m
The train goes through the cave, the distance is:
4320 + 540 = 4860m
= 1214 M / min
（440*3+750*4+30*16+15*4）/4=110*3+750+30*4+15=330+750+120+15=1215
750m
In the arithmetic sequence {an}, if a1 + A4 + A7 = 39, A3 + A6 + A9 = 27, then the sum of the first nine terms of the sequence is ()
A. 297B. 144C. 99D. 66
In ∵ arithmetic sequence {an}, a1 + A4 + A7 = 39, A3 + A6 + A9 = 27, ∵ 3A1 + 9D = 393a1 + 15d = 27, the solution is A1 = 19, d = - 2, ∵ S9 = 9 × 19 + 9 × 82 × (− 2) = 99
5x-2(x+2)-3[x-2(3-5x)+7]
=5x-2x-4-3(x-6+10x+7)
=3x-4-3(11x+1)
=3x-4-33x-3
=-30x-7
A school is going to organize teachers and students to have a spring outing. There are 22 teachers. There are two travel agencies a and B, both of which have the same pricing and preferential conditions. Teachers in travel agency a are free, and students are charged with 20% discount; teachers and students in travel agency B are charged with 7.50% discount. Which travel agency should the school choose?
22 times 0.75 equals 16.5, that is to say, B travel agency pays 16.5 yuan more than a in terms of teachers
If there are X students, the cost of travel agency a and B is the same
0.8x-16.5=0.75x
The solution is x = 330
Therefore, when the number of students is equal to 330, the choice of a and B travel agencies is the same
When the number of students is more than 330, it is appropriate to choose B travel agency
When the number of students is less than 330, it is appropriate to choose a travel agency
Hope to adopt!
In the arithmetic sequence {an}, if a1 + A4 + A7 = 39, A3 + A6 + A9 = 27, then the sum of the first nine terms of the sequence is ()
A. 297B. 144C. 99D. 66
In ∵ arithmetic sequence {an}, a1 + A4 + A7 = 39, A3 + A6 + A9 = 27, ∵ 3A1 + 9D = 393a1 + 15d = 27, the solution is A1 = 19, d = - 2, ∵ S9 = 9 × 19 + 9 × 82 × (− 2) = 99
3(x+2.5)=5x
3x+7.5=5x
2x=7.5
x=3.75
The solution of the original equation is x = 3.75
Seek the best
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