"Practical problems and linear inequalities of one variable" Inequality and inequality group PPT courseware 3

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"Practical problems and linear inequalities of one variable" Inequality and inequality group PPT courseware 3

Give it a try:

Solve the following inequalities and represent the solutions on the number line:

(1) 5(x+3)>4x-1

(2) 2(x+5)≤3(x-5)

Store A: After purchasing a total of 100 yuan worth of goods in this supermarket, any additional purchases will be charged at 90% of the original price.

Store B: After purchasing a total of 50 yuan worth of goods in this supermarket, any additional purchases will be charged at 95% of the original price.

Analysis: The starting point of store A’s discount plan is after the shopping amount reaches 100 yuan;

The starting point for store B’s discount plan is after the purchase amount reaches 50 yuan.

The requirement for shopping is to get greater discounts.

The place to choose is store A or store B.

Getting a bigger discount mainly depends on the amount of your purchase.

We can divide shopping money into three ranges:

0~50 yuan, 50~100 yuan, more than 100 yuan

Who are smart consumers?

Xiaoying plans to spend 21 yuan to buy pens and notebooks. It is known that each pen is 3 yuan and each notebook is 2 yuan. She bought 3 notebooks. Please help her calculate. How many pens can she buy at most?

1. Set the unknowns appropriately according to the meaning of the question

2. Use algebraic expressions to express each process quantity

Each pen costs _____ yuan, and the pen costs _____ yuan.

It cost _____ yuan to buy a notebook.

The money was spent on buying ______ and ____________. Its mathematical expression is ____________.

According to the question, the total price of her pens and notebooks requires ______________.

3. List the inequalities

Expressed as a mathematical expression: ______________.

Two teachers led several students to travel (the travel fee was paid uniformly). They contacted two travel agencies that quoted 100 yuan/person. The preferential conditions of travel agency A were: two teachers paid in full, and the rest were 25% off ( 75% of the quoted price); Travel Agency B’s preferential conditions are: 20% off for everyone (80% of the quoted price). Which travel agency is more affordable?

Solution: Suppose there are x students,

Then travel agency A’s fee is 100×2＋100×0.75 x = 200+75x

B’s travel agency fee is (2+x)×100×0.8=160+80x

1) When 200+75x>160+80x, x < 8, that is, when the number of students is less than 8, it is more affordable to choose travel agency B

2) When 200+75x=160+80x, x=8, that is, when the number of students is 8, the cost of choosing travel agency A and B is the same

3) When 200+75x<160+80x, x>8, that is, when the number of students is greater than 8, it is more economical to choose travel agency A

Keywords: Teaching courseware for inequalities and groups of inequalities, teaching courseware for practical problems and linear inequalities of one variable, PPT courseware for the second volume of seventh-grade mathematics published by the New People's Education Press, downloading of seventh-grade mathematics slide courseware, downloading PPT courseware for inequalities and groups of inequalities, practical problems and Download PPT courseware of linear inequalities of one variable in .ppt format

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Update Time: 2024-06-29

This template belongs to Mathematics courseware People's Education Press Seventh Grade Mathematics Volume 2 industry PPT template

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