1 + 2 

= 3 

nha bn

=3600

nhaNatsu x Lucy

tích mik mik tích lại

5 + 6 + 7 

= 11 + 7 

= 18 

nha bn

Đáp án

30+10=40

ĐS:40

Ta có: 45¹⁰.5²⁰=(3².5)¹⁰.(5²)¹⁰

                      =3²⁰.(5²)⁵.25¹⁰

                     =3¹⁵.3⁵.25⁵.25¹⁰

                     =3⁵(3¹⁵.25¹⁵)

                     =3⁵.75¹⁵

Do đó:  \(\frac{45^{10}.5^{20}}{75^{15}}=\frac{3^5.75^{15}}{7^{15}}=3^5\)

11 x 14 = 154

Viết tập hợp A  mà 10 < x < 100  

A = { 11 ; 12 ; 13 ; 14 ;.. 99 }

 k nha bn

Viết lại câu:

1. He spent lots of time doing this experimen

⇒It took him lots of time to do this experiment.

2. It took me all the morning to prepare for lunch

⇒I spent all the morning preparing for lunch.

3. Anna spent three days visiting VN

⇒It took Anna three days to visit VN.

4. It took my son three years to study in this college

⇒my son spent three years studying in this college.

5. I spent two hours doing my home work ereryday

⇒It takes me two hours to do my home work everyday.

6. They spent ten days painting this house

⇒It took them ten days to paint this house.

7. Last week , she spent 2 days tidying her room

⇒It took her 2 days to tidy her room last week.

8. They used to go to school in half an hour

⇒It used to take them half an hour to go to school.

⇒They used to spend half an hour going to school.

We often spent 30 minutes reviewing our lesson before class

⇒It often took us 30 minutes to review our lesson before class.

10. It took him hours to fly from hanoi to london

⇒He spent hours flying from Hanoi to London.

dễ thế mà cũng hỏi