Xiaoxiao's birthday, dad bought a birthday cake. Xiaoxiao ate 1 / 6, Dad ate the rest of the 1 / 5, mom ate the rest of the 1 / 4, who ate more cake

Xiaoxiao's birthday, dad bought a birthday cake. Xiaoxiao ate 1 / 6, Dad ate the rest of the 1 / 5, mom ate the rest of the 1 / 4, who ate more cake

1-1/6=5/6 5/6x1/5=1/6 (5/6-1/6) x1/4=1/6
All three of them ate one sixth as much

During May 1, a shopping mall launched a 20% discount for the whole store. Holding the VIP card, you can continue to discount on the basis of 20% discount. Xiaoming's mother bought goods priced at 10000 yuan with the VIP card, saving 2800 yuan in total, and then enjoyed it again with the VIP card______ There is a discount

According to the meaning of the question: 10000-10000 × 80% × X10 = 2800 solution: x = 9, you can enjoy a 10% discount on VIP card

1+3+5+7+…… 99+100+101—2+4+6+…… 100=?
We need to talk about ideas

5247

When m, n take what value, the cube of polynomial-5x-2mx square + 2x + 4-x square-3nx-1 is a cubic binomial

The original formula = - 5x & sup3; + (- 2m-1) x & sup2; + (2-3n) x + 3
It's a cubic binomial
There are only two
Then the middle two coefficients are 0
-2m-1=0
2-3n=0
m=-1/2,n=2/3

The purchase price of a commodity is 2000 yuan per piece. If it is sold at a 20% discount on the price, the profit of each commodity will be reduced by 60%. What is the price of the commodity?
The application of equation in grade one of junior high school,
All heroes, help~
】Thank you very much~

Set the price as X Yuan
x×80%-2000=（x-2000)×（1-60%）
0.8x-2000=0.4x-800
x=3000

200+199-198-197+196+195-194+.+8+7-6-5+4+3-2-1
be equal to?

Divide it into four numbers, four numbers
There are 25 groups
The results of each group were 4
So the answer is 100

How to find the derivative of y = (arcsin (x / 3)) ^ 5?

y'=[(arcsin(x/3))^5]'
=5(arcsin(x/3))^4*(1/3)*[1/√(1-x^2/9)]
It's really hard to have a process, because it's just a step
The idea is: This is a compound derivative, so every layer of function must be derivative
The more difficult one is (arcsinu) '= 1 / √ (1-u ^ 2)

3.56×38.5+0.7×356+9.15×35.6．

3.56×38.5+0.7×356+9.15×35.6=35.6×3.85+70×35.6+9.15×35.6=35.6×（3.85+70+9.15）=35.6×83=2954.8．

What's after one-third, two-quarters, three-quarters and four-quarters
Cnfvhbfdb fluorescent lamp method

5/99
Denominator calculation process
3+12=15
15+12+8=35
35+(12+8)+8=63
63+(12+8+8)+8=99
The molecules are one in turn
Positive and negative are positive for one number, negative for the next, and so on

The square of a-2a + 1 / 1-A = 1-A

Any real number with a ≠ 1