Math problems, the master advances, so there are additions

Suppose the length, width and height are x, y, z, and the expansion factor is n times, and assume that the total number of edge lengths t is 7 times more than the original volume: n*x*y*z=(7+1)*x*y*z, so n=8

According to the sum of the edge lengths and 100 cm more than the original.

Derived. t*n=100+t

So the sum of the edge lengths t = 100 7 cm.

Enlarged x times the original to V

x^3*v-xv=7v ,x=2

The length of the original edge is long and enlarged for l

l=xl=l+100，l=100

l=200

Let the length, width, and height of the original cuboid be a, b, and c, respectively. Then the original volume is abcThen let the enlarged multiple be x, then the current volume is axbxcx solution to get abcx 3 can get the equation abcx 3 abc=7 then x=3 7 then the total length is 3 7a+3 7b+3 7c solution to get 3 7(a+b+c) should be 100 cm longer than the original length, so get equation 3 7(a+b+c)-(a+b+c)=100 solve to get (3 7-1)(a+b+c)=100 can know that the original length is 100 (3 7-1) Therefore, the enlarged length can be found to be 100 (3 7-1)+100

The integer part of a decimal place, the lowest digit is (number) digits, the counting unit is (1), the highest digit of the decimal part is (tenth) digits, and the counting unit is (.

The number of 260 thousandths is (, and the number that rewrites it as hundredths is (. , of the five numbers, the smallest is (, the largest is (, and the middle is (.

43 divided by 7 = 6 1, if the dividend and the divisor are both enlarged by a factor of 100, then the quotient is (6) and the remainder is (100).

4 times a number is 6 less than the quotient of 108 divided by 6, and this number is (3).

1.Let the distance be l, and go back and forth for a total of 2l, and the time t=l n+l m, so the average velocity is 2l t=2(1 n+1 m)=2(n+m) mn2Ignoring the conditions, the car needs x yuan, p yuan = 70% of the car**=, and you can buy a car if you are still short.

It takes 30 7 p yuan to find it.

3.Excluding xy terms, -3k+1 3=0, k=1 94The question is wrong, and the front of c is unified as a plus sign, or a unified minus sign, otherwise there is no solution.

a(-3)^5+b(-3)^3+c（-3）-8=-（a3^5+b3^3+c3）-8

（a3^5+b3^3+c3-8+8）-8

1,2mn/(m+n);2. I didn't make it clear, if it was a loan; 3,1/9；4，-24

2.Let the adjacent smaller integer be a, then according to the question: that is, to prove: (a+1) 2-(a 2) is an odd number, simplified to the original formula = 2a+1, you say that 2a must be an even number, then 2a+1 needless to say.

3.Original = [(2-1) (2-1)](2+1)(2 2+1)(2 4+1)......2^32+1)+1

Then you see (2-1) (2+1) = (2 2-1), and then this (2 2-1) can be (2 4-1) ...... with the square difference of (2 2+1).You just do the math like this, and the final result is 2 64, so you can press the calculator yourself.

4.（a+b)^2=a^2+2ab+b^25.(n+2)^2-n^2=4(n+1)

Agree, let the integer be n (n+1) -n = (n+1-n)(n+1+n)=2n+1

2n+1 is an odd number.

5.（n+2）²-n²=4*（n+1）

Question 1 The answer is a squared -9

Question 2 Agree with her.

Set the two adjacent integers to a, a+1 (a is any real number).

then a*a-(a+1)*(a+1)=-(2a+1) shows that the square difference of two adjacent integers must be odd.

Question 4 Found (a+b) = a b +2ab

1、s=(a+3)(a-3)=a^2

2. The sum of two adjacent numbers is an odd number, and the difference is also an odd number. Odd multiplies odd or odd.

5. n 2-(n+2) 2=(n+2) 2-n 2 will not do the rest.

1: Solution: Except for the family income of 10,000 yuan, the sum of the income of 99 families is a yuan

When the largest number 10,000 is incorrectly entered into 100,000 yuan, the average value of the income of these 100 households is (a+100000) 100= (a 100)+1000 (yuan), and the average value of the actual income of these 100 families is (a+10000) 100= (a 100)+100 (yuan), (a 100)+1000)-(a 100)+100)=900 (yuan).

2: If a set of data is multiplied by the average of a set of new data at the same time, then the average of the original data is.

1. The total income is more than 90,000, and the average is 900 in 100 families, so the difference between the average value of Liangling socks and the actual average value calculated according to the wrong number is 900 yuan.

2 Multiply the total by 100 and multiply the average by 100 to get the average of the new ridge.

The average varies in equal proportion to the total.

The average of the original data is:

Adding two absolute values to know that the two absolute values are zero, so that a is equal to five and b is equal to minus three, so the answer is seven out of five.

1.Volume = 1 3 * height * radius 2

So height = 3 meters.

2.The image ratio is a fixed value.

So AB actual distance 480 24 * 5 = 100 km 3Equation is the same as 1

The volume of the cylinder is 2*2*3* =1 3*3*3* *height = height of the cone volume = 4 cm.

days, so days = 48

=> h=3

2ab distance is equal to 5 24*480=10km

3.The two volumes do not change, so: pi*2 2*3=1 3*pi*3 2*h = > h = 4 cm.

4.Assuming all x days, then: 250 5 = 2400 x = > x = 48, so it will take 48-5 = 43 days.

(1) v = base area * height = 2 2 * h so height = 1 solution x = 100

So it's 100 km.

3.In the same way, if the height is h, the wax melt does not change the total volume, so the volume is equal, so 2 2 *3=3 2 *h is solved to h=4 3cm

Number of days, so there are 43 days left and 43 days to complete.

m km cm : 250 = : 2400 solution = 48 so 43 days.