Xiaohua has 14 pieces of 5 yuan and 10 yuan RMB, a total of 100 yuan. How many pieces of 5 yuan and 10 yuan RMB?

Xiaohua has 14 pieces of 5 yuan and 10 yuan RMB, a total of 100 yuan. How many pieces of 5 yuan and 10 yuan RMB?

Let 5 yuan have X sheets
5x+（14-x）10=100
x=8
10 yuan sheets = 14-8 = 6

Multiplication science is equal to learning mathematics
What's the number? What's the learning

Learn from science * 11 = subject (subject + Learning)
Learning = subject + 1 (subject + Learning up to 1) and number = 1
And 6 + 5 = 11
Guxue = 6

For rational numbers x, y, define a new operation: X * y = ax + by + C, where a, B, C are constants, and the right side of the equation is the usual addition and multiplication operation
For rational number x, define a new operation: X * y = ax + by + C, where a and C are constants, and the right side of the equation is the usual addition and multiplication operation. Given that 1 * 2 = 9, (- 3) * 3 = 6, 0 * 1 = 2, find the value of 2 * (- 7)

∵x*y=ax+by+c
∴1*2=a+2b+c=9(x=1,y=2)
（-3）*3=-3a+3b+c=6(x=-3,y=3)
0*1=b+c=2(x=0,y=1)
∴a=2,b=5,c=-3
∴2*（-7）=2*2-7*5-3=-34

Add or subtract from 1 to 8 in order to be equal to 19

1+2-3-4+5-6+7+8+9=19

Given xy = - 10, | x + y | = - (x + y), and X, y are integers, find the value of X-Y
There are four answers, ± 11, plus or minus 7, reasoning clearly

When xy = - 10, X and y are opposite
|X + y | = - (x + y) leads to x + y ≤ 0
10=1×10=2×5
x. If y are all integers, then
x. Y values are - 1 and 10 or 1 and - 10 or 2 and - 5 or - 2 and 5
therefore
x-y=-1-10=-11
or
x-y=1-(-10)=11
or
x-y=2-(-5)=7
or
x-y=-2-5=-7
therefore
The value of X-Y is ± 11 or ± 7

Huamei shampoo costs 30 yuan per bottle, 5 bottles for free and 8 bottles for free
Buy 5 bottles and get one free. How much is the average one?
Buy 8 bottles and get 2 free. How much is an average bottle?

Buy 5 free 1:5 * 30 / 6 = 25 per bottle
Buy 8 get 2 free: 8 * 30 / 10 = 24 per bottle
Buying 10 bottles in partnership is the most cost-effective, while two people buy together: compared with buying 4 for 1, buying 8 for 2 (10 bottles) is the most cost-effective
If you have to buy 12 bottles together, buy 5 bottles each and get 1 free (6 bottles)
Hope to solve your problem

If x ＞ 0, y ＞ 0 and 2 / x + 8 / y = 1, how to find the minimum value of XY
We must use the mean value theorem, but because we are looking for XY, we can't regard the front as the form of a + B, so a + B ＞ = root AB can't be calculated
So how can I change my mind? First of all, I'm rather stupid, so can I give a detailed answer to each one?

+ =1
=
32 xy-32
The minimum value of XY is 64
If you don't copy it, you just square 2 / x + 8 / y = 1 to get 4 / x + 64 / y + 32 / xy = 1
And 2 / X * 8 / y

I want to buy a hamburger

I'd like a hamburger.
Or I want a hamburger

2 out of 11 times () = 9 out of 4 times () = 1 out of 4 times () = 0.1 times () = 3 out of 4 + () thank you
It's urgent. Bart, everybody

The whole formula is as follows:
2/11X11/2
=9/4X4/9
=1/4X4
=0.1X10
=3/4+1/4
=1
This is very simple. First, make sure that the final result is equal to 1, then it's OK?

On the map with a scale of 1:6000000, the distance between the two places is 25cm. At 9:30 a.m., a plane flew from place a to place B,
It arrived at 10:45 am. How many kilometers per hour does this plane fly?

You can draw a graph, a grid graph, and you'll know