cho các số hữu tỉ sau tìm điều kiện của a để x là số nguyên

a) x = a+2/a+1

b) x = a+5/a+3

c) x = a-4/a-2 

d) x = a-1/a-2

m.n giải chi tiết ra giúp mik

We know that we will pollute the environment if we do not use materials wisely. People have founded many programmes to save materials and protect the environment. 3Rs is one of them. 3Rs stands for Reduce, Reuse and Recycle. Reducing means we reduce the amount of waste we produce. This is the best way to help the environment. If we do not reduce the waste, we will pollute our environment more seriously. Reusing is using the items again. For example, plastic bags can be reused if it is still new. We should not throw away reusable things but store and use them for other purposes. Recycling is changing the waste materials into new products. For example, we recycle waste paper to make carton boxes. We should recycle as many things as possible. If we reduce, reuse and recycle our resources, we will save energy and money. Moreover, we will help to prevent pollution and global climate change.

1. What will happen if people do not use materials wisely? .....................................................................................................................

2. What does 3Rs stand for? .....................................................................................................................

3. What does "reducing" mean? .....................................................................................................................

4. What will happen if we do not reduce the waste? .....................................................................................................................

5. What is "reusing"? .....................................................................................................................

6. Should we throw away reusable things? .....................................................................................................................

7. What is "recycling"? .....................................................................................................................

8. Can we recycle waste paper to make a new product? .....................................................................................................................

m.n giúp mik với

một bác nông dân thu hoạch  cam và mang cam ra chợ bán.buổi sáng bác đã bán 40 kg , ứng với 5/8 số cam . buổi chiều bác bán được 2/5 số cam buổi sáng

a)hỏi các bác nông dân đã mang bao nhiêu kg cam ra chợ bán?

b)tính số kg cam buổi chiều bán được?

c) tính số kg còn lại chưa được bán

m,ngiúp mik với