34 of a number is 15 more than 25 of 60. What's the number? (solved by equation)

34 of a number is 15 more than 25 of 60. What's the number? (solved by equation)

Let this number be x, 34x-60 × 25 = 15, & nbsp; & nbsp; 34x-24 = 15, & nbsp; & nbsp; & nbsp; & nbsp; 34x = 39, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; X = 52; a: this number is 52

How to solve the equation X-6 / 5 = 1 / 9 of mathematics in Volume 1 of grade 5

6 of (X-5) = 1 of 9
6*9=x-5
x=54+5
x=59

Sometimes the light reflected from the blackboard "shakes" some students' eyes. In order to protect students' eyes, please put forward some suggestions to change this situation

The surface of blackboard will become smoother after a long time of use. When the strong light shines on the blackboard, mirror reflection will occur. As a result, some students can't see the words on the blackboard and "shake" their eyes. In order to protect their eyes, you can roughen the blackboard surface (or replace it with ground glass blackboard, or temporarily move your position or use some non reflective blackboard Materials make blackboard

A circular paper with a diameter of a is divided into several equal parts and cut into an approximate rectangle along the radius. The circumference of the rectangle is () cm
The radius of the circle is () cm, and the area of the circle is () square centimeter

The circumference of a rectangle is: π a + a cm
Radius: 0.5A cm
Area: 0.25 π A & # 178; square centimeter

5.2.4.3 how to calculate to get 24. 7.9.3.6 how to calculate to get 24

（5+3+4）*2=24
（9-7+6）*3=24

Finding the range of function f (x) = 1-x2 / 1 + x2

Let y = (1-x & # - 178;) / (1 + X & # - 178;) and (y + 1) x & # - 178; + Y-1 = 0. When y = - 1, - 1-1 = - 2 ≠ 0, y can't be equal to - 1. When y ≠ - 1, △ = 0-4 (y + 1) (Y-1) ≥ 0, and - 1 ≤ y ≤ 1, - 1 < y ≤ 1

In the middle of a 55 meter long and 45 meter wide rectangular green space, two vertical paths of the same width will be built. The remaining area that can be used for greening is 2000 thousand square meters

The total area of rectangular green space is 55 * 45 = 2475
So the area of the path is 2475-2000 = 475
Let the path width be X
So the area of the path is 55 * x + 45 * x = 100 * X
Because the two paths intersect, we need to subtract the area of the intersecting part X ^ 2
So 100 * x-x ^ 2 = 475
Solve the equation to get x = 5 or x = 95 (over 55, so remove)
That is, the width of the path is 5

2.1, 2.5, 2.9, 18.4, 18.8, 19.2, 34.7, 35.1 and 35.5 are put into the table, and the sum of each row, column and diagonal is equal

2.5 35.5 18.4
34.7 18.8 2.9
19.2 2.1 35.1

Given that the sequence {an} satisfies A1 = 1, A2 = - 13, an + 2-2an + 1 + an = 2n-6 (I) let BN = an + 1-an, find the general term formula of the sequence {BN}; (II) when finding the value of N, an is the minimum (it is not necessary to find the minimum value of an)

（I）∵bn=an+1-an，∴an+2-2an+1+an=bn+1-bn=2n-6∴bn−bn−1＝2(n−1)−6，bn−1−bn−2＝2(n−2)−6，… By adding these n-1 equations, BN − B1 = 2 = 2 [1 + 2 +...] +(n − 1)] − 6 (n − 1) ｜ BN = N2 − 7n − 8, that is, the general term formula of sequence {BN} is BN = N2 − 7n − 8 (Ⅱ) if an is the minimum, then an ≤ an-1 and an ≤ an + 1, that is, bn-1 ≤ 0 and BN ≥ 0 ｜ N2 − 7n − 8 ≥ 0 (n − 1) 2 − 7 (n − 1) − 8 ≤ 0. Note that n is a positive integer, and the solution is 8 ≤ n ≤ 9} when n = 8 or n = 9, the value of an is equal and the minimum

Room. With the side length of 5 decimeters square brick floor, need 128, if changed to 8 decimeters square brick floor, need how many?
Proportional solution

There's no specific size. I can't figure out how much to cut. It's not accurate. At least it needs more than 50 pieces. If the room size is 4m * 8m, it's just 50 pieces