E.

Giải:
\(35 - 3 \left(\right. x - 1 \left.\right) = 32\)
\(35 - 3 x + 3 = 32\)
\(38 - 3 x = 32\)
\(- 3 x = - 6\)
\(\Rightarrow x = 2\)

Đáp số: x = 2

F.

Giải:
\(18 - \left(\right. 7 - 2 x \left.\right) = 17\)
\(18 - 7 + 2 x = 17\)
\(11 + 2 x = 17\)
\(2 x = 6\)
\(\Rightarrow x = 3\)

Đáp số: x = 3

G.

Giải:
\(\left(\right. x - 5 \left.\right) - 14 = 6\)
\(x - 19 = 6\)
\(\Rightarrow x = 25\)

Đáp số: x = 25

H.

Giải:
\(2 \left(\right. x - 3 \left.\right) - 7 = 3\)
\(2 x - 6 - 7 = 3\)
\(2 x - 13 = 3\)
\(2 x = 16\)
\(\Rightarrow x = 8\)

Đáp số: x = 8

L.

Giải:
\(15 : x - 2 = 1\)
\(\frac{15}{x} = 3\)
\(15 = 3 x\)
\(\Rightarrow x = 5\)

Đáp số: x = 5

\(\frac{x}{2 , 3} + 4 , 5 = 5 \times 1 , 5 = 7 , 5\)

\(\frac{x}{2 , 3} = 3 \Rightarrow x = 3 \times 2 , 3 = 6 , 9\)

Đáp số:6,9

113

Giả sử số có ba chữ số M = 100a + 10b + c,
trong đó \(a , b , c\) là các chữ số (a ≠ 0).

Số viết ngược lại N = 100c + 10b + a.

Ta xét hiệu:

\(M - N = \left(\right. 100 a + 10 b + c \left.\right) - \left(\right. 100 c + 10 b + a \left.\right)\)

Thu gọn:

\(M - N = 99 a - 99 c = 99 \left(\right. a - c \left.\right)\)

Vì \(99 = 3 \times 33\) nên 99 luôn chia hết cho 3.

Suy ra:

\(M-N=99\left(\right.a-c\left.\right)\text{lu}\hat{\text{o}}\text{n chia h}\overset{ˊ}{\hat{\text{e}}}\text{t cho}\text{3}.\)

Vậy hiệu của số có ba chữ số và số viết ngược lại của nó luôn chia hết cho 3.

1. Teenagers now seem to behave more violently than in the past.

2. She has a physical handicap; however, she has become a successful woman.

3. My brother is not interested in playing board games.

4. She is passionate about talking with her mom about classical music.

5. The more you do yoga, the fitter you will get.

6. John failed the exam for his laziness.

7. They are getting more and more passionate.

8. She is hooked on walking under the rain.

9. It rained heavily, so we couldn't keep on cleaning.

10. You must show up; otherwise, the party won’t take place.

11. Could you carry my suitcase for me, please?

12. There was a traffic jam; however, we managed to arrive at the train station on time.

13. He had a more fascinating idea than hers.

14. I am crazy about checking Facebook every morning.

15. You must watch TV every day, or you won’t know much of the hottest news.

oki

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