Very development of thinking math problems, help the little brother put! To the process,! The proces

x^4+x^2+1

x^2+1)^2 - x^2

x^2-x+1)(x^2+x+1)

x^2 / (x^4+x^2+1)

x^2 / (x^2-x+1)][x / (x^2+x+1)]7 * x / (x^2+x+1)]

x^2-x+1)/x = 1/7 ，x^2+x+1)/x = 1/7 + 2 = 15/7

So: [x (x 2+x+1)] = 7 15 So: x 2 (x 4+x 2+1) = 49 15 This is a theoretical value, but there is no solution.

Because. x/x^2-x+1=7

x=7x^2-7x+7

7x^2-8x+7=0

x^2+8/7x+1=0

x^2+1=8/7x

x+1/x=8/7

x^2+1/x^2

x+1/x)^2-2

Because x 2+1 x 2>0

So x doesn't exist.

x 2 x 4+x 2+1 also does not exist.

Let 3x+4y=a be Eq. 1 and 4x+3y=5 be Eq. 2

Multiply Equation 1 by 4 to get 12x+16y=4a, multiply Equation 2 by 3 to get 12x+9y=15 to get the equation you get: 7y=4a-15, let Equation 3 multiply Equation 1 by 3 to get 9x+12y=3a, multiply Equation 2 by 4 to get 16x+12y=20 to get the equation you get: 7x=20-3a, let Equation 4 be known from the title:

The solution of the equation is non-negative, so equation 3>0 and equation 4>0 is 4a-15>0, and the solution is a>15 4

20-3a>0, solution a<20 3

exists, which can be solved by a system of equations, x=(20-3a) 7, y=(4a-15) 7At the same time, make xy greater than or equal to 0It can be solved that 15 4 < = a< = 20 3

So we get a = 4,,, 5,6

Solve systems of equations. 3x+2y=m+1,4x+y=m,get.

x=(m-1)/5

y=(m+4) 5, by x<2, y<2, so.

m-1)/5<2

m+4) 5<2, m<11, m<6

So m<6

3x+2y=m+1 (1)

4x+y=m (2)

1)-(2) 2 De:

3x+2y-8x-2y=m+1-2m

5x=1-m x=(m-1)/5

Bring in (2) to:

4×(m-1)/5+y=m

y=(m+4)/5

x y is less than 2

So. m-1)/5<2 m<11

m+4)/5<2 m<6

So m<6

8x+2y=2m，3x+2y-（8x+2y）=m+1-2m5x=-m-1

x=m/5+1/5

x is less than 2m 5 + 1 5 is less than 2

m is less than 912x+8y=4m+4

12x+3y=3m

12x+8y-（12x+3y）=4m+4-3m5y=m+4

y is less than 2m+4 is less than 2

m is less than -2, so m is less than -2

If there are y people, then from "if each room lives 4 people, then there are 19 people without a room" gets: 4x=y-19 that is, y=4x+19, and from "each room lives with 6 people, then there is a dormitory that is not empty and dissatisfied": 6 (x-1) then 6 (x-1) < 4x+19 <6x, and the corresponding y solution is: y=59,63,67.

Solution: There are x rooms with Y people.

y-4x=19

0 substituting one formula into two formulas to sort it out.

0<25-2x<6

So I got it. x1=10 y1=59

x2=11 y2=63

x3=12 y3=67

There are x dormitories.

0<4x+19-6(x-1)<6

0<20-2x<6

7 so x may be 8 or 9, corresponding to 4*8+19=51 and 4*9+19=55, respectively

The number of rooms is set to m and the number of people is set to n

The equation is: 4*m + 19 = n .1）6*m > n ..2) This type means that if a room with 6 people is still empty, it will not be satisfied.

6*(m-1) Just solve it, this should be easy to solve. Use substitution, hehe.

Let m=2 start with n from (1) and substitute n m into (2) and (3) if it is true.

If there are x rooms in the dormitory, the number of students is (4x+19) 6 (x-1) 4x+19 6x

x is an integer. x=10，11，12

6x>4x+19 and 4x+19>5x2x>19 x> and 19>x

Number of dormitories: 10, 11, 12, 13, 14, 15, 16, 17, 18, Number of students: 59, 63, 67, 71, 75, 79, 83, 87, 91

(This question can't just give me the answer, you have to say the method, you can use the hypothetical method, or you can draw a picture) Remove a letter from the word in parentheses to make it a new word and complete the sentence.

A completes 1 120 per day

B is done every day:

B does it alone need:

1 1 40 = 40 days.

Passenger cars travel 1 8 per hour for the whole journey

Trucks travel 1 12 per hour

Encounter required: 1 (1 8 + 1 12) = 24 5 hours.

When they met, the bus traveled the whole way:

The distance between the meeting point and the midpoint is the whole journey

ab distance: 54 1 10 = 540 km.

The weight of each piece of alloy is in units of 1, and the total weight of the two pieces is 2

The first piece contains copper: 2 (2+5)=2 7

The second piece, containing copper: 1 (1+3)=1 4

Total copper: 2 7 + 1 4 = 15 28

Total tin: 2-15 28=41 28

The ratio of copper to tin in the new alloy is 15 28:41 28 = 15:41 10% of the first journey, which is equal to 1 3 of the second journey

Distance A is equal to distance B: 1 3 10% = 10 3 Distance B: kilometers.

Distance: km.

The distance between east and west is kilometers.

A and B total: 170 + 90 = 260 tons.

After adjustment, 6 5 of B is equal to 75% of A

A is equal to B: 6 5 75% = 8 5

B of the total: 1 (8 5 + 1) = 5 13

B has grain: 260 5 13 = 100 tons.

B bin increased: 100-90 = 10 tons.

Adjustment plan: Take out 10 tons from A and put it in B.

Question 1 Because A 1 12 did. B did 5 days and did 5 24 so; B did 3 24 in 5 days

That is, 1 8 5 * 8 = 40, so it takes 40 days for B to do it, give points, and then do it for you.