My hat and book are on the table, but where is my watch

My hat and book are on the table, but where is my watch

There is an English book and two dictionaries on the desk

There is an English book and two dictionaries on the desk.
Pay attention to the principle of "nearby"~

Given the function f (x) = a Λ χ (a > 0 and a ≠ 1), there are two points P (2, Y &;;) and Q (1, Y &;), if y &; - Y &;
For detailed explanation
If y &; - Y &; = 2, then the root of the equation f (x) = 2 is

a^2=y1
a^1=y2
y1-y2=2
From the above three formulas, a = 2
From F (x) = 2, x = 1

The number of male workers in the knitting factory accounts for 40% of the total number of full-time workers. The female workers are divided into three workshops, with an average of 60 people in each workshop?

The total number of employees in the plant is (60 × 3) / (1-40%) = 300,

The solution of the equations 3x + 5Y = 6,6x + 15y = 15 is also the solution of the equation 3x + KY = 10, and the value of K is obtained

3x+5y=6,6x+15y=15
The solution is x = 1, y = 3 / 5
Substituting 3x + KY = 10
k=35/3

China won several gold medals in the 2012 London Olympics

At present, China has 18 gold, 11 silver and 5 copper
2012 London Olympic medal list:
Total amount of gold, silver and copper by country / Region
1 China 18 11 5 34
2 United States 18 9 10 37
As of 16:00 on August 3, Beijing time

If there is no XY term in polynomial 2 (x2-xy-3y2) - (3x2-ax + Y2), what is a equal to

Original form
=2x²-2xy-6y²-3x²+axy-y²
=2x²-3x²+axy-2xy-6y²-y²
=-x²+(a-2)xy-7y²
If there is no XY term, then
a-2=0
a=2

In the school sports meeting, the number of students in the fourth grade is twice as many as that in the third grade, 120 more than that in the third grade
Fourth grade math problem, did not learn x equation

If there are X students in the third grade, there are 2x students in the fourth grade
2x×2-x=120
4x-x=120
3x=120
x=40
There are 2x = 2 × 40 = 80 students in the fourth grade

One math problem, quick solution: there are 25 multiple-choice questions in one test, 4 points for right one and 1 point for wrong one. If you want to test 80 points, how many questions do you have to solve,

Let's face the X-way
4x-(25-x)=80
5x=105
x=21
A: we have to deal with 21 questions

The ratio of a, B and C is 4 to 7 to 9. The average of the three numbers is 40, and the three numbers are (), (), ()

3*40÷（4+7+9）=6
6×4=24
6×7=42
6×9=54
The three numbers are (24), (42), (54)