6 The boss promised that none of his co-workers had to work overtime the next month

7 The shop assitant asked the man which jeans I had already tried on

8 The zookeeper told the children not to feed the animals

6. The boss promised ( that ) none of his/her co-workers had to work overtime the following month.

7. The shop assistant asked the man which jeans he had already tried on 

8. The zookeeper told the children not to feed the animals

2D nha em, sau ''model verb'' ta dùng V nguyên thể

Chọn A

A

A

a, Áp dụng t/c dtsbn:

\(\dfrac{a}{b}=\dfrac{c}{d}=\dfrac{a+c}{b+d}\)

b, Áp dụng t/c dtsbn:

\(\dfrac{a}{b}=\dfrac{c}{d}=\dfrac{2021a}{2021b}=\dfrac{2021a-c}{2021b-d}\)

c, Ta có \(\dfrac{a}{b}=\dfrac{c}{d}\Rightarrow\left(\dfrac{a}{b}\right)^2=\left(\dfrac{c}{d}\right)^2\)

Áp dụng t/c dtsbn:

\(\left(\dfrac{a}{b}\right)^2=\left(\dfrac{c}{d}\right)^2=\dfrac{a^2}{b^2}=\dfrac{c^2}{d^2}=\dfrac{a^2+c^2}{b^2+d^2}\)

 ^{\(x^2=9/25 x=0,6 hoặc x=(-0,6); x^2=0,09 x=0,3 hoặc (-0,3); căn bậc 2x=2 x=2\)}

\(72-3\left|x\right|=9\)

\(3\left|x\right|=72-9=63\)

\(\left|x\right|=63:3=21\)

\(\Rightarrow x=\pm21\)

\(72-3\left|x\right|=9\)

\(3\left|x\right|=63\)

\(\left|x\right|=21\)

x= 21 hoặc x= -21

\(-12\left(x-5\right)+7\left(3-x\right)=9\)

\(-12x+60+21-7x=9\)

\(-19x=-72\)

\(x=\dfrac{72}{19}\)

Câu 3: 

a: ĐKXĐ: \(x\ne2\)

b: \(A=\dfrac{\left(x-2\right)^2}{5\left(x-2\right)}=\dfrac{x-2}{5}\)

B