Xiao Gang has read a 250 page story book for five days, with an average of 26 pages a day, and the rest 30 pages a day. How many days will it take to finish?

(250-5 × 26) △ 30 = (250-130) △ 30 = 120 △ 30 = 4 (days) a: it will take another 4 days to finish

Xiao Li asked Xiao Gang to think of a number at random, and then multiplied it by 5 minus 7, then multiplied it by 2, and subtracted the above formula with - 14, finally the result was analyzed

This number is X - 14 - (x multiplied by 5-7) multiplied by 2 = result
-14 - (5x-7) × 2 = result
-10x = result
So the result divided by - 10 is this X

Fill in the blanks, grade 6, Volume 2
1. A road can be built 30 meters a day in 80 days. If it is built 40 meters a day, how many days can it be built?
(1) In the question () and () are two kinds of related quantity, known () is certain, () and () are proportional
(2) If the repair can be completed in X days, the column proportion formula is ()

1. Work efficiency, work time and workload are fixed, but work efficiency and work time are in inverse proportion
2、30：40=x：80

If a rectangle has an area of 180 square meters and its length is reduced by 3 meters, it will become a square. What is the circumference of the rectangle? (process)

Let the original length be x and the width be y
Then xy = 180
y=x-3
There is: X (x-3) = 180
The solution is: x = 15, y = 12
So the perimeter is 54

The 12th power of a minus the 12th power of B
Factorization

The square difference formula is used for multiple decomposition, that is, (the 6th power of a + the 6th power of B) * (the 3rd power of a + the 3rd power of B) * (the 3rd power of a - the 3rd power of B), and then the cubic sum difference formula is used for decomposition, (A & sup2; + B & sup2;) * (the 4th power of a - A & sup2; B & sup2; + the 4th power of B) * (a + b) (A & sup2; - AB + B & sup2;) * (a-b) (A & sup2; + AB + B & sup2;)

It takes 24 seconds for a train to pass through a 375 meter long tunnel at the same speed and 16 seconds to pass through a 231 meter long tunnel

Speed
(375-231) △ 24-16) = 144 △ 8 = 18 m / S
Length 18x24-375 = 432-375 = 57M

As shown in the figure, in the quadrilateral ABCD, ∠ a = ∠ BCD = 90 °, BC = CD, CE ⊥ ad, the perpendicular foot is e, verification: AE = CE

In the △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and ∈ BCF ⊥ B \\88; B, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and △ CDE, in △ BCF and ∈ BCF and ⊥ CDE, in ∈ BCF and ⊥ CDE, in ⊥ BCF and ⊥ CDE, in ⊥ BFF CE

How many light years is the sun away from the earth

The earth's orbit around the sun is not circular, but elliptical. Therefore, perihelion and aphelion will be produced, with an average distance of 150 million kilometers, which is called 1AU in astronomy. 1AU means that the average distance between the earth and the sun is about 150 million kilometers, which is exactly the eighth power of 1.496 * 10

The charge of a telecom company is 0.2 yuan for three minutes of calls in the city, and 0.1 yuan for every minute more than three minutes
The functional relationship between the telephone fee y yuan and the call time t (t is greater than or equal to 3, t is a positive number) is

Y=0.2+0.1*(T-3) (T≥3)
Y=0.1T-0.1 (T≥3)

As shown in the figure, the diagonal lines AC and BD of diamond ABCD intersect at O, AC = 10 and BD = 24
Seek the height of the diamond. Draw your own picture

∵ the quadrilateral ABCD is a diamond, ∵ AC ⊥ BD, OA = 1 / 2Ac = 5,0b = 1 / 2bd = 12, with Pythagorean theorem, ab = 13, the area of diamond = 1 / 2Ac ≁ 8226; BD = AE ≁ 8226; BC, ∵ AE = 120 / 13

Xiao Gang has read a 250 page story book for five days, with an average of 26 pages a day, and the rest 30 pages a day. How many days will it take to finish?