d, \(\left(\dfrac{3}{4}\right)^7.x=\left(\dfrac{3}{4}\right)^5\)

Số cái ghế 1 người đóng trong 1 giờ là:

\(42:6=7\)(cái ghế)

Số cái ghế 8 người đóng trong 1 giờ là:

\(7\times8=56\)(cái ghế)

Đáp số: 56 cái ghế

_Does____ Lan___walk___ (walk) to school with you?

\(1-\dfrac{1}{2}+2-\dfrac{2}{3}+3-\dfrac{3}{4}-4-\dfrac{1}{3}-2-\dfrac{1}{2}-1\)

\(=\left(1-1\right)+\left(2-2\right)+\left(3-4\right)+\left(-\dfrac{1}{2}-\dfrac{1}{2}\right)+\left(-\dfrac{2}{3}-\dfrac{1}{3}\right)-\dfrac{3}{4}\)

\(=0+0+\left(-1\right)+\left(-1\right)+\left(-1\right)-\dfrac{3}{4}\)

\(=-3-\dfrac{3}{4}\)

\(=\dfrac{-12}{4}-\dfrac{3}{4}\)

\(=\dfrac{-15}{4}\)

__Do__ you (have) __have_____ any new friends?

câu 1)

a)\(\dfrac{3}{7}< \dfrac{5}{7}\)

b)\(1>\dfrac{14}{15}\)

c)\(\dfrac{8}{9}>\dfrac{12}{18}\)

câu 2) B

câu 3) D

câu 4) D

câu 5)

a) \(\dfrac{3}{4}+\dfrac{5}{4}=\dfrac{3+5}{4}=\dfrac{8}{4}=2\)

b) \(\dfrac{2}{3}+\dfrac{3}{4}=\dfrac{8}{12}+\dfrac{9}{12}=\dfrac{8+9}{12}=\dfrac{17}{12}\)

c) \(\dfrac{1}{3}+\dfrac{5}{7}=\dfrac{7}{21}+\dfrac{15}{21}=\dfrac{7+15}{21}=\dfrac{22}{21}\)

câu 6)

a) \(\dfrac{7}{8}-\dfrac{6}{8}=\dfrac{7-6}{8}=\dfrac{1}{8}\)

\(\dfrac{3}{12}-\left(\dfrac{6}{12}-\dfrac{3}{10}\right)\)

\(=\dfrac{3}{12}-\dfrac{6}{12}+\dfrac{3}{10}\)

\(=\dfrac{-3}{12}+\dfrac{1}{10}\)

\(=\dfrac{-1}{4}+\dfrac{1}{10}\)

\(=\dfrac{-10}{40}+\dfrac{4}{40}\)

\(=\dfrac{-6}{40}\)

\(=\dfrac{-3}{20}\)

Dù tôi đi xa, luôn nhớ về quê cha đất tổ.