Chọn đáp án: B. Các câu 1 – 2 – 4 – 6 – 8

Chọn C

Bài 4:

a: Ta có: \(-\left|x+1.1\right|\le0\forall x\)

\(\Leftrightarrow-\left|x+1.1\right|+1.5\le1.5\forall x\)

Dấu '=' xảy ra khi x=-1,1

b: Ta có: \(-4\left|x-2\right|\le0\forall x\)

\(\Leftrightarrow-4\left|x-2\right|+10\le10\forall x\)

Dấu '=' xảy ra khi x=2

\(\frac{12}{1}:\frac{6}{5}+\frac{4}{7}=\frac{60}{6}+\frac{7}{4}=\frac{10}{1}+\frac{7}{4}=\frac{40}{4}+\frac{7}{4}=\frac{47}{4}\)

\(\left(\frac{5}{6}+\frac{3}{4}\right)\cdot\frac{8}{19}=\frac{38}{24}\cdot\frac{18}{9}=\frac{38}{24}\cdot2=\frac{76}{24}=\frac{19}{6}\)

\(\left(\frac{7}{4}-\frac{5}{3}\right)\cdot\frac{2}{3}=\frac{1}{12}\cdot\frac{2}{3}=\frac{1}{13}\)

câu 1 : 62/35

câu 2 : 2/3

câu 3 : 1/18

nhớ tk m nhé

câu 1: 12:6/5+4/7=47/21

câu 2: (5/6+3/4):19/8=2/3

câu 3: (7/4-5/3):3/2=1/18

6.Although he had a good salary, he was unhappy in his job
In spite of his good salary he was unhappy in his job

7.) In spite of the forecast it stayed fine.
-> Although rain was predicted, it stayed fine

8.Although the team played well, they lost.
In spite of/Despite the fact that the team played well, they lost

9.

In spite of all our warnings, he left the camp without taking his rifle.

⇒Although we had warned, he left the camp without taking his rifle.

10.=> despite my nephew 's terrible behaviour,i am still fond of him

11.In spite of his age, Mr Benson runs seven miles before breakfast.

-> Though he is old age, Mr Benson runs seven miles before breakfast.

Câu 1)

1/5*x=4/6

x=4/6/1/5

x=10/3

Câu 3)x/6*5/8=5/12

x/6=5/12/5/8

x/6=2/3

x/6=4/6

Vây x=4

Câu 3)

5/9/3/x=5/27

3/x=5/9/5/27

3/x=3

Vây x=1

câu 1 10/3

câu 2 4/6

câu 3 3/1

Câu 2.

\(R_{13}=\dfrac{R_1\cdot R_3}{R_1+R_3}=\dfrac{30\cdot60}{30+60}=20\Omega\)

\(R_{tđ}=R_2+R_{13}=45+20=65\Omega\)

\(I_m=\dfrac{U}{R}=\dfrac{130}{65}=2A\)

\(I_{13}=I_m=2A\)

\(U_{13}=U-U_2=U-I_2\cdot R_2=130-2\cdot45=40V\)

\(R_1//R_3\Rightarrow U_1=U_3=U_{13}=40V\)

\(I_3=\dfrac{U_3}{R_3}=\dfrac{40}{60}=\dfrac{2}{3}A\)

Câu 3.

\(R_1//R_2\)

\(\Rightarrow R_{tđ}=\dfrac{R_1\cdot R_2}{R_1+R_2}=\dfrac{10\cdot30}{10+30}=7,5\Omega\)

\(U_1=U_2=U_m=15V\)

\(I_1=\dfrac{U_1}{R_1}=\dfrac{15}{10}=1,5A\)

\(I_2=\dfrac{U_2}{R_2}=\dfrac{15}{30}=0,5A\)

\(I_m=I_1+I_2=1,5+0,5=2A\)

C

C nha

c