In class 62, the ratio of boys to girls is 9:7. There are six more boys than girls. How many students are there in class 62

In class 62, the ratio of boys to girls is 9:7. There are six more boys than girls. How many students are there in class 62

(9 + 7) * 6 / (9-7) = 48

The number of boys in class 1 is 8 / 9 of that of girls. After one girl is transferred, the number of boys is 6 / 7 of that of girls. How many boys and girls are there in class 1
Urgent ah, kneel down to beg

If there were x girls, there were 8x Boys / 9 girls
The results are as follows
（X+1）*6/7=8X/9
56X=54（X+1）
2X=54
X = 27
The number of boys is 8x / 9 = 24

Boys are 5 / 9 of the class. Girls are 5 less than boys. How many boys and girls are there

There are 25 boys and 20 girls

Do you have the answer after 1-3-1 of geography mapping training in middle school?

Direct map, can help you do

6300 plus 15 times 700 plus 300 minus 1024 plus 12356 equals?

600+15×700+300-1024+12356=22732

The derivative of piecewise function, finding the derivative of point a and point B
Let f (x) = ax + 1, X ≤ 2 and x ^ 2 + B, x > 2
It can be derived at x = 2, and the constants A and B can be obtained
I have a solution as follows:
Since f (2-0) = f (2 = 0), 2A + 1 = 2 ^ 2 + B
Because f '(x) = a, x2
So the left limit of F '(x) is equal to a, and the right limit of F' (x) is equal to 4
I'd like to know how the "f '(x) = a, X2" step comes about?

First calculate f (2) = 2A + 1
For F to be differentiable at 2, f must be continuous at 2,
f(2 - 0) = f(2 + 0) = f(2) = 2a + 1,
That is 2A + 1 = 2 ^ 2 + B,
We should look at the left and right derivatives again
But your solution is to use the derivative limit theorem
That requires the derivative f '(x) of F (x) on both sides of 2 (excluding 2)
When x < 2, near x, f (x) is the same as the elementary function ax + 1
Therefore, f '(x) = (AX + 1)' = a
When x > 2, near x, f (x) is the same as the elementary function x ^ 2 + B
Therefore, f '(x) = (x ^ 2 + b)' = 2x
This is the origin of "f '(x) = a, X2"
The so-called "near X" is "in a sufficiently small neighborhood of point X". As long as X is not equal to zero, you can get a very small neighborhood so that it does not contain 0. In this way, f (x) in this small neighborhood is the same as that elementary function, so the derivative is the same

Simple operation of 9999 * 3333 + 2222 * 3334

9999×3333+2222×3334
=1111×29997+1111×6668
=1111×(29997+6668)
=1111×36665
=40734815

It's a multiple of two and a multiple of three 15 (write a number) 4 (write a number) 3 (write a number)
Another question:
At the same time, it is a multiple of 2, 3 and 5, 27 (a number) 31 (a number) (a number) four digits

150, 42, 36 the second question is 27603120

The coefficients of the numerator denominator of the fraction 0.5x-2y / 2x / 3 + 0.5y are reduced to integers

（2x+0.5y）/(0.5x-2y/3)
=(60x+15y)/(15x-20y)
=(12x+3y)/(3x-4y)

1+2+3+4+5+6………… +98+99+100=?

S＝1+2+3+4+5+6………… +98 + 99 + 100, write it upside down
S＝100＋99＋98＋………… ＋2＋1
Add the two expressions to get the
2S＝（1＋100）＋（2＋99）＋…… （99＋2）＋（100＋1）
＝101×100
So s = 101 × 50 = 5050