Elementary 1 math problems, inequalities, junior 1 math inequalities practice problems

Solution: Substituting x=2 into (m+2)x=2 obtains:

m+2)×2=2

m=-1 substitute m=-1 into (m-2)x-3, and get:

1-2）x＞—3

x 10, -1, -2 is the solution of the inequality.

m 2) x 2 bring x 2 in.

m 2) 2 2 m 1

Then m 1 put in (m 2) x 3

1－2）x＞－3

3x＞－3x＜1

So 0 1 is the solution.

If the solution of equation (m+2) x=2 is x=2, think about it, what is the solution set of inequality (m-2) x —3? Try to solve the inequality of those numbers in the five numbers 2,-1,0,1,2.

m+2)x=2, that is, (m+2)=1 m=-1, substituting m=-1 x=2 into (m-2)x-3 to obtain (-1-2)*2>-3 is impossible. So there is no solution to this inequality.

Solution: Bring x=2 into the original formula to get (m+2)*2=2 simplification to find m=-1, and then bring m=-1 into (m-2)x —3 to find x<1, so 0, -1, -2 are all solutions to the inequality.

Generally, when doing inequality problems, x and y are regarded as variables, and the rest of the letters are regarded as known quantities or constant quantities, with special exceptions.

What about the topic? The application question has been solved.

1) 3-(a-5)>3a-4 (a<3)2) -5x+3<2x+1 (x>1 and 1/3)3)3-4[1-3(2-x)] greater than or equal to 59 (x less than or equal to -3)4)6 (1-1x/1 - 3) greater than or equal to 2+1/5 (10-15x) (x greater than or equal to -2)5)5)7x-13>3/3 3x-8 (x>-3)6)4x-10<15x-(8x-2) (x>-4)7) x-2-2-x>x-2/3 (x>2)8) x-2/6 - x-4/3 Greater than or equal to 0 (x less than or equal to 4) 9) x-1 out of 3 - 110 <110) 2 (5-3x) >3 (4x+2) 11) 1x>212) 7x-2 (x-3) <1613) 3 (2x-1) <4 (x-1) 14) 2-6 (x-5) greater than or equal to 4 (3-2x) 15) 7 + 3x<5+4x16)5-x(x+3)>2-x(x-1)17)x-2(x+1/2)less than or equal to 1-3(1-x)18)3(x-1)+2(1-3x)<519)1x-1=0/3 is the same solution as inequality (x-2)(x-5)<=0, then the value range of a is ? Solution of inequality (x-2)(x-5) <=0 2<=x<=5 Solution of inequality x(x-a)>=0 When a>0, x>a or x<0 a=0, inequality x 2>=0 is constant When a<0, the solution of x>0 or x=0 is a>=5, the inequality group has no solution, and is an empty set 2<=a<5, the inequality group a=0 is the same solution as inequality (x-2)(x-5) <=0 then a<22Finding the solution of the natural numbers of the inequality group 3(x-1)+2 5x+3, (x-1) 2+x 3x-4 The solution of an inequality group is x>-2 The solution of the second inequality group is x 7 3 So-21 x>1 3 4

The system of equations 3x+2y=m+1, 4x+3y=m-1, to make x>y, find the value of m. To write the process 3x+2y=m+1 (1) 4x+3y=m-1 (2) (2)*5-(1)*7 20x+15y-21x-14y=5m-5-7m-7 -x+y=-2m-12 x>y So y-x<0 -2m-12<0 2m>-12 m>-6 These are what I found out from the paper, the first few questions have answers in parentheses, and the last few questions will trouble you to calculate and check it yourself! Hope it helps you a little bit!

This is a basic calculation question, don't lose points for the basic, practice more, other multiple-choice questions, fill-in-the-blank questions, applications, all have a basis for calculation, do a good job of calculation, and the rest should not be done! I don't know if you're satisfied?

A travel agency 240+120x

B Travel Agency 240*

If A is discounted, then 240+120x <240* i.e. x >4 and when x <4, B is discounted.

When x=4, it is just as expensive.

Solution: The cost of the first travel agency is 240+240*

The fee for option B travel agency is: 240*

240+120x-(144+144x)

96-24x

When 96-24x>0, that is, x<4, when the number of students is less than 4, travel agency B will be discounted.

When 96-24x=0, i.e., x=4, the number of students equals 4, the cost is the same.

When 96-24x<0, that is, x>4, the number of students is about 4, travel agency A discounts.

Let 240 + 120x=

x=4When there are 4 students, the average ticket price of the two travel agencies is 144 yuan, which is equal.

When the number of students is less than 4, B travel agency will be discounted;

When the number of students is greater than 4, travel agency A will receive a discount.