Question 7 on page 102 of the first volume of Mathematics

Question 7 on page 102 of the first volume of Mathematics

Let the speed of the aircraft be x km / h when there is no wind
five
（x+24）*2—=3（x-24）
5 6
2—x+68=3x-72
6 1
—x=140
six
X = 840 range: (840 + 24) * 3 = 2592 (km)

p55.8

10

One bus and one minibus can seat 75 people in total. Four minibuses and one bus carry the same number of people. How many people can each minibus and bus seat?

Noodles 15, 60

Taylor formula of Ln ((1 + x) / (1-x)) at x = 0 Ask for advice!
In fact, the most important thing is to simplify first. Now it's done. Just divide it into two forms and subtract them

It's too long to play. You know the expression of Taylor's formula. It's actually the expansion when x0 = 0. It's actually McLaughlin's formula. It's easy to solve it by reading the book

If LG2, LG (2x-1) and LG (2x + 3) are in arithmetic sequence, then the value of X is equal to ()
A. 1b. 0 or 32c. 32D. Log25

If LG2, LG (2x-1) and LG (2x + 3) form an arithmetic sequence, then LG2 + LG (2x + 3) = 2lg (2x-1), LG [2 · (2x + 3)] = LG (2x-1) 2 can be obtained from the operation property of logarithm, and the solution is 2X = 5 or 2x = - 1 (not conforming to the property of exponential function, rounding off), then x = log25, so D is selected

English translation
Translation into English

He bought a birthday present for me

I have a piece of land 60 meters long and 16 meters wide. How many mu of land are there

60*16/666.7=1.439928

Finding the integer solution of the equation xy-2x-2y + 7 = 0 (x ≤ y)

xy-2x-2y+7=0
(x-2)(y-2)=－3
X-2 is different from Y-2, and X and y are integers,
The common factor group of - 3 is - 1 × 3,1 × (- 3)
Because x ≤ y
When X-2 = 1, Y-2 = - 3
That is, x = 3, y = - 1 (rounding off)
When X-2 = - 1, Y-2 = - 3
That is, x = 1, y = - 1 (rounding off)
When X-2 = - 3, Y-2 = 1
That is, x = - 1, y = 3
When X-2 = 3, Y-2 = - 1
That is, x = 5, y = 1 (rounding off)
So x = - 1, y = 3

How to write fashionable English words

fashion

In the self-study class, math teacher Wang gave the students an exercise: when x = 2011, Qiu seeks the value of polynomial (2x + 3) (3x + 2) - 6x (x + 3) + 5x + 16. After the problem is finished, Xiao Gang said: the condition given by the teacher, x = 2011, is redundant. Xiao Liang said: if you don't give this condition, you can't find the result, so it's not redundant. Smart students, who do you think is right? Why?

（2x+3）（3x+2）—6x（x+3）+5x+16
=6x^2+13x+6-6x^2-18x+5x+16
=22
The value of polynomial (2x + 3) (3x + 2) - 6x (x + 3) + 5x + 16 is independent of X
Xiao Gang is right, x = 2011 is superfluous