Lời giải:
Gọi số thứ nhất là $a$ và số thứ hai là $b$.

Theo bài ra ta có:
\(\left\{\begin{matrix} 4b+5a=18040\\ 3a-2b=2002\end{matrix}\right.\Leftrightarrow \left\{\begin{matrix} 5a+4b=18040\\ 6a-4b=4004\end{matrix}\right.\)

\(\Rightarrow 5a+6a=18040+4004\)

\(\Leftrightarrow 11a=22044\Leftrightarrow a=2004\)

\(b=\frac{3a-2002}{2}=2005\)

em nhân lần lượt như nhân vs 1 chứ số từ phái sang trái, cứ hết mỗi chữ số thì lùi vào 1 đơn vị là đc. Tính xng cả 3 hàng thì em cộng vào như bth, giống như nhân vs số có 2 chữ số ấy. Chỉ thêm 1 hàng đằng sau thôi maf` ^^ 

1 poverty

2 decision

3 worried

4 awake

5 singers

7 northen

8 disappeared

9 difference

10 unimportant

11 windy

12 portable

13 sensibly

14 painting

15 mainly

SOS😥👉🏳👈

1. Ha went to doctor's yesterday because he was sick

2. He ate some spinach last night

3. The doctor said that the vegetable could be dirty so he must wash carefully

4. The doctor gave him some medicine

5. He felt better after take medicine

III)

36:A

37:B

38:B

39:A(mk ko chắc lắm)

40:B

IV)

1:It is about 100 km from Hanoi to Thanh hoa

2:How long is it from Hai duong to Hue

3:My father used to live in a small village when he was a child

4:Although he is young,he performs excellently

5:There are five rooms in Hoa's house

6:The red car is cheaper than the black car

7:Mr hung has fewer days off than Mr Minh

8:Let's play chess tonight

9:The children enjoy reading comics

a) 4Na + O₂ --t^o--> 2Na₂O

b) \(n_{Na_2O}=\dfrac{24,8}{62}=0,4\left(mol\right)\)

4Na + O₂ --t^o--> 2Na₂O

0,8<--0,2<-------0,4

=> m_Na = 0,8.23 = 18,4 (g)

c) m_O2 = 0,2.32 = 6,4 (g)

V_O2 = 0,2.24,79 = 4,958(l)

not very difficult to learn Math

if I took some photographs?

will be built in my neighborhood

if I liked watching football match

learnt English for 3 years