Math problems for the first time, and math inequality practice problems for the first time

Solution: (2a-b)x+a-5b>0

2a-b)x>5b-a

The set of solutions for inequalities is x<7 10

2a-b<0

x<(5b-a)/(2a-b)=7/10

14a-7b=50b-10a

8a=19b

Let a 19=b 8=k, then a=19k, b=8k2a-b<0

38k-8k<0

k<0 solution ax>b gets 19kx>8k

x<8/19

The solution set for inequality ax>b is x<8 19

From (2a-b)x+a-5b>0, there is (2a-b)x>5b-a, but the result is x<7 10, obviously there is a variant, there is 2a-b<0, so x<(5b-a) (2a-b)=7 10, there is 27a=45b, a b=5 3, and because 2a-b<0, a,b must be less than 0, so the solution set of ax>b is x<3 5

x<24/57

Solution: (2a-b)x+a-5b>0

2a-b)x>5b-a, because its solution set is x<7 10, so 2a-b<0, and 5b-a 2a-b=7 10

Therefore, b=24a 57, substituting into 2a-b<0 can obtain a<0, so ax>b, the solution is x<24 57

There are 5 people in one dormitory, and 14 people are not fitted. A dormitory is equipped with 7 people, and there is a surplus in the dormitory. Q: How many dormitories are there and how many students are there?

1.Because 2x<4 so x<2, because x<2 so a-1>0 If a-1<0 will get x greater than a certain number, because the inequality divided by a negative judgment number changes direction, so the solution of inequality (a-1)x4a+5 so there is (5a-1) 2>4a+5 solution of this inequality.

a<-11/3

3.To solve the inequality to get x k 3, if you want to solve the positive integer of the inequality 1 2 3, that is, 3 k 3<4 solve this inequality to get it.

9≤k<12

Hope it helps you ...

1) Because x 2, a-1 0, (a+5) (a-1)=2 so a=7

2) Solve the first equation, x=(5a-1) 2, and because x 4a+5, so (5a-1) 2 4a+5 a -11 3

3) x k noisy bump 3 and object car because the positive integer solution of x is 1,2,3, so k cover bump is greater than or equal to 3, less than 4,1 k 4 3

1. Solution: It took ten hours to drive from upstream A to downstream B at a constant speed.

The available equation is s=(v+3)*10

It took less than 12 hours to return from B to A at a constant speed.

Equation s (v-3)*12 is obtained

Synaccio v 3 or v 33

2. Solution: Let the original length of the bullet-starved simple spring be x and the progress coefficient is k, then k (

k (get k=2000n m.)

x=3, solution: let x, y, z respectively represent the number of 1 angle, 5 angles, and 1 yuan: x+5y+10z=70(1).

x+y+z=15 （2）

x, y, z are all integers and do not exceed the total value of 7 yuan.

1)-(Closed sum 2) : 4y+9z=55

Because y z are positive integers, let x=0, x=1, x=2, x=3........., respectively

x=10 can be found as x=5 y=7 z=3

4. Solution: I bought x rabbits a year ago.

x+2<=2/3(2x-1)

x+2<=4/3x-2/3

1/3x>=8/3

x>=8

That is, at least 8 were bought.