a) 25-(15-19+13)+(12-18+10)

 = 25-15+19-13+12-18+10

=20

b)(53-76)-[-76-(-53)]

=53-76+76+53

=106

\(5^{20}:\left(5^{15}\cdot6+5^{15}\cdot19\right)\)

= \(5^{20}:5^{15}\cdot6+5^{20}:5^{15}\cdot19\)

= \(5^5\cdot6+5^5\cdot19\)

= \(3125\cdot6+3125\cdot19\)

= \(18750+59375\)

= \(78125\)

What is in the kitchen?

\(\dfrac{-9}{x}=\dfrac{-3}{\dfrac{4}{49}}\)

<=> \(\dfrac{-9}{x}=\dfrac{-147}{4}\)

<=> \(-9\cdot4=-147\cdot x\)

<=> \(-36=-147\cdot x\)

\(x=\dfrac{-36}{-147}=\dfrac{36}{147}\)

1) Where do we live?

2) Where is the museum?

3) Is there a hospital in my neighbourhood?

4) Is there a drugstore next to my house?

5) Where does Lan's mother work?

6) Where does Ba's father work?

7) Where do they live?

8) Where is Minh's house?

1: to repair

2: learning

3: playing

4: inviting

\(\left|7x+1\right|=20\)

<=> \(7x+1=\pm20\)

TH1: 7x + 1 = 20

=> \(x=\left(20-1\right):7=\dfrac{19}{7}\) (loại vì x thuộc Z)

TH2: 7x + 1 = -20

=> \(x=\left(-20-1\right):7=-3\) (chọn)

Vậy x = -3 thỏa mãn đề bài.

Đáp án là B: should.