The number ratio of science and technology books to story books in the library is 2:3. In the morning, a batch of newly purchased science and technology books are set in the library, and after sorting, the number ratio of science and technology books to story books is 10:9. In the afternoon, the number ratio of science and technology books to story books is 5:6. Only 100 more science and technology books have been purchased than story books How many science books and story books are there?

The original ratio of science and technology books to story books is: 2:3 = 6:9. In the morning, a batch of newly purchased science and technology books are set up in the library. After sorting out, the ratio of science and technology books to story books is 10:9. Therefore, the purchase of science and technology books is 10-6 = 4. In the afternoon, the newly purchased story books and story books are put into the library. At this time, the ratio of science and technology books to story books is: 5:6 = 10:12; the purchase of story books is 12-9 = 3（ So the total number was 100 × (4-3) × (6 + 9) = 1500. A: there were 1500 science and technology books and story books in the library

There are 100 story books in the school library. The number of comic books is four fifths of story books and two thirds of science and technology books. How many science and technology books are there?
Good answer plus reward points

Comic book = 100 × 4 / 5 = 80
Science and technology book = 80 / 2 / 3 = 120

There are 13 Science and technology books in our bookcase, half of them are story books, and the rest are comic books. How many are comic books?

1-13-12, = 23-12, = 16

How to solve LIM (√ (4x & # 178; - 8x + 5) + 2x + 1), X → - ∞?

lim(x→-∞) (√(4x²-8x+5) +2x+1)
=lim(x→-∞) (√(4x²-8x+5) +2x+1) * (√(4x²-8x+5) -2x-1) / (√(4x²-8x+5) -2x-1)
=lim(x→-∞) [4x²-8x+5 - (2x+1)²] / (√(4x²-8x+5) -2x-1)
=lim(x→-∞) (-12x +4) / (√(4x²-8x+5) -2x-1)
=lim(x→-∞) (12 -4/x) / (√(4-8/x+5/x²) +2+1/x)
At this point, 1 / X and 1 / X both tend to zero
therefore
Original limit = 12 / (2 + 2) = 3

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

As a birthday present

How many square meters and acres is 100 meters long and 100 meters wide? How many square meters and acres is 50 meters long and 50 meters wide

Ten thousand square meters, 15 mu. Two thousand five hundred square meters, 3.75 mu

Finding the integer solution of the equation xy-2x-2y = 3
Factorization
3q, I don't know who to give ~. Another question: which method of factorization (how did you make it

（x-2）（y-2）＝7
x. Y is an integer
X-2, Y-2 are integers
x-2＝1,y-2=7
x-2=7,y-2=1
x-2=-1,y-2＝－7
x-2=-7,y-2＝－1
x=3,y=9
x=9,y=3
x=1,y=-5
x=-5,y=-1

It's about eating for 26 words

apple banana candy doughnut egg
Fren-fries green-pepper hamburger ice-cream
Jam kiwifruit lemon mango noodles orange pizza quail rice sangwich tea U (no)
Watermeion should not be YZ

In a math class, Mr. Hao gave a question for the students: when x = - 1 / 2, x = - 2, x = 0, x = 1, x = 1 / 2, find the value of fraction 1 / x ^ 2-2x + 3

2) The meaningful fraction means that the denominator is not zero because x ^ 2-2x + 3 = (x-1) ^ 2 + 2, and because (x-1) ^ 2 is greater than or equal to 0, so (x-1) ^ 2 + 2 is greater than or equal to 2, that is, x ^ 2-2x + 3 is greater than or equal to 2

There are 100 story books in the school library. The number of comic books is four fifths of story books and two thirds of science and technology books. How many science and technology books are there? Good answer plus reward points