Each can of coke is 3.5 yuan. The supermarket recycles empty cans of coke, which is 0.2 yuan. Teacher Li uses 100 yuan to buy Coke for children. How many cans can he buy at most?

Each can of coke is 3.5 yuan. The supermarket recycles empty cans of coke, which is 0.2 yuan. Teacher Li uses 100 yuan to buy Coke for children. How many cans can he buy at most?

100 △ 3.5 = 28 2 yuan
28 × 0.2 × 2 = 7.6
7.6 △ 3.5 = 2 6 yuan
Up to 28 x 2 = 30

Finding the maximum and minimum of Z = XY on x ^ 2 + y ^ 2 = 1
It's x ^ 2 + y ^ 2

Let x = ksina, y = kcosa, so K ^ 2Sin ^ 2A + K ^ 2cos ^ 2A ≤ 1, namely K ^ 2 ≤ 1, namely - 1 ≤ K ≤ 1, then z = xy = ksinakcosa = k ^ 21 / 2 × 2sinacosa = 1 / 2K ^ 2sin2a, namely - 1 / 2 ≤ 1 / 2sin2a ≤ 1 / 2, namely - 1 / 2K ^ 2 ≤ 1 / 2K ^ 2sin2a ≤ 1 / 2K ^ 2, namely - 1 / 2K ^ 2 ≤ 1 / 2K ^ 2sin2a ≤ 1 / 2K ^ 2

A kind of juice in a beverage shop costs 1 yuan more than B kind of juice. Xiao Ming and his four friends asked for 2 cups of a kind of juice and 3 cups of B kind of juice, which cost 17 yuan in total. What's the unit price of these two kinds of juice?

Let a juice X Yuan, then there is: 2x + 3 (x-1) = 17, the solution is x = 4, then X-1 = 3

Calculation: (- C / a squared b) times (- AB / C squared) squared △ A / BC

: (- C / a square B) multiplied by (- AB / C Square) / - A / BC
=-C & # 179; the sixth power of a part B & # 179; × A & # 178; B & # 178; the fourth power of C Part X BC part a
=-The fourth power of a & # 178; B & # 179; C is the seventh power of a and the fourth power of B & # 179; C
=-The fifth power of a

The distance between a and B is 300 km. A passenger car and a freight car drive from a to B respectively. The passenger car arrives in 6 hours and the freight car arrives in 5 hours. How much faster is the speed of the freight car than that of the passenger car?

The speed of truck is 300 △ 5 = 60 km / h
The speed of the bus is 300 △ 6 = 50 km / h
The speed of freight car is faster than that of passenger car: (60-50) △ 50 = 20%

Given X-Y = - 3, - x + 3Y = 2, find the value of the algebraic formula x2-4xy + 3y2

∵ X-Y = - 3, - x + 3Y = 2, ∵ primitive = (X-Y) (x-3y) = - (X-Y) (- x + 3Y) = - (- 3) × 2 = 6

On the map with a scale of 1:3000000, the distance between a and B is 40km. Two cars leave from a and B at the same time and pass by
12 hour meeting. It is known that car a travels 48 kilometers per hour and car B how many kilometers per hour?

It's 40 centimeters
The actual distance is 40 × 3000000 △ 100000 = 1200 km
1200÷12-48=52
A: car B travels 52 kilometers per hour

Solution equation: (29-2x) (22-2x) = 478.5
solve equations:
1、(29-2x)(22-2x)=478.5
2、{[5+（5-1.25x）]/2}x=5

To solve the equation:
1、(29-2x)(22-2x)=478.5
638-58x-44x+4x^2=478.5
4x^2-102x+159.5=0
x^2-25.5x+39.875=0
[x-12.75]^2=122.6875
x-12.75=+/-11.08
x1=23.83
x2=1.67
2、{[5+（5-1.25x）]/2}x=5
[(10-1.25x)/2]x=5
[5-0.625x]x=5
5x-0.625x^2-5=0
x^2-8x+8=0
[x-4]^2=8
X-4 = + / - 2 2
X1 = 4 + 2 2
X2 = 4-2, 2

A and B set out from ab at the same time and went opposite each other. Seven hours later, they met, and then they continued to drive at the original speed for two hours. At this time, a was still far away from B
240 kilometers, B car is 360 kilometers away from A. how many kilometers are there between a and B?

Distance between a and B: (240 + 360) / (1-1 / 7X2) = 840 (km)

If the difference between moving the decimal point one place to the right and one place to the left of a decimal is 34.65, then the original number is ()
A. 3.1B. 3.5C. 3.8D. 3.9

A: the original number is 3.5