x =0,75

Số chẵn lớn nhất có 5 chữ số khác nhau là :

   86420 

1A: Hi, what are you doing?

2L: Let's pick up some holiday brochures

1E: Holiday brochures? Why?

2B: We need to book our summer holiday soon or all the good deals will have been taken

1H: Actually… it's already booked. Sorry!

2K:Well, phone up and cancel it. Even if you must pay a fine, cancel it!

1C: Calm down! I was joking. You really have to try to develop a sense of humour

2F: Look, you shouldn't booked anything without discussing with me first. Do you understand?

1G :OK, but we don't have to get brochures. They are a waste of paper. We should search online. It's better for the environment

2I:If you're so worried about the environment, we shouldn't go on holiday at all. Flying produces a lot of CO2!

1D: Who said anything about flying? We needn't fly anywhere. I'm thinking of a walking holiday in Belgium. I've already found a company online that organises tours.

Học tốt nha !!!

Ta có: 

3²⁰⁰⁹ = 3.3²⁰⁰⁸ = 3.(3⁴)⁵⁰² = 3.81⁵⁰² = 3.(...1) = (...3)

7²⁰¹⁰ = (7⁴)⁵⁰².7² = (...1)⁵⁰².49 = (...1).49 = (...9)

13²⁰¹¹ = (13⁴)⁵⁰² . 13³ = (...1).(...7) = (...7)

=> b = (...3).(...9).(...7) = (...9)

=> b có chữ số hàng đơn vị là 9

Bán kính của hình tròn đó là : 

            15,7 : 3,14 : 2 = 2,5(m)

Diện tích của hình tròn đó là;
            2,5 x 2,5 = 6,25 (m²)

                    Đáp số : 6,25 m² 

X=150