a) \(=\left(13\dfrac{2}{7}+2\dfrac{5}{7}\right):\left(-\dfrac{8}{9}\right)\)

\(=16:\dfrac{-8}{9}=\dfrac{-8\cdot\left(-2\right)\cdot9}{-8}=-18\)

b) 

\(=\left(\dfrac{-6}{11}\cdot\dfrac{11}{-6}\right)\cdot\dfrac{7\cdot10\cdot\left(-2\right)}{10}\)

\(=-14\)

c) \(=\dfrac{-1}{2}\cdot\dfrac{4}{3}\cdot\dfrac{-7}{2}\)

\(=\dfrac{-1\cdot2\cdot2\cdot\left(-7\right)}{2\cdot3\cdot2}=\dfrac{7}{3}\)

\(\dfrac{16^3.3^{10}+120.6^9}{4^6.3^{12}+6^{11}}=\dfrac{\left(2^4\right)^3.3^{10}+3.5.2^3.\left(2.3\right)^9}{\left(2^2\right)^6.3^{12}+\left(2.3\right)^{11}}\)

\(=\dfrac{2^{12}.3^{10}+3.5.2^3.2^9.3^9}{2^{12}.3^{12}+2^{11}.3^{11}}=\dfrac{2^{12}.3^{10}+5.2^{12}.3^{10}}{2^{12}.3^{12}+2^{11}.3^{11}}\)

\(=\dfrac{2^{12}.3^{10}\left(1+5\right)}{2^{11}.3^{11}.\left(2.3+1\right)}\)\(=\dfrac{2^{12}.3^{10}.6}{2^{11}.3^{11}.7}=\dfrac{2.2}{7}=\dfrac{4}{7}\)

\(a.\left[-\dfrac{6}{11}.\dfrac{11}{-6}\right].\dfrac{7}{10}.\left(-20\right)=1.7.\left(-2\right)=-14\)

\(b.\dfrac{-1}{2}:\dfrac{3}{4}.\dfrac{-7}{2}=\dfrac{7}{4}:\dfrac{3}{4}=\dfrac{7}{3}\)

\(c.\dfrac{93}{7}:-\dfrac{8}{9}+\dfrac{19}{7}:\dfrac{-8}{9}=\left(\dfrac{93}{7}+\dfrac{19}{7}\right):-\dfrac{8}{9}=\dfrac{-9}{8}.\dfrac{112}{7}=-18\)

a) 2/9 - (1/20 + 2/9)

= 2/9 - 1/20 - 2/9

= (2/9 - 2/9) - 1/20

= 0 - 1/20

= -1/20

b) -3/14 + 2/13 + (-25/14) + (-15/13)

= (-3/14 - 25/14) + (2/13 - 15/13)

= -2 - 1

= -3

c) -3/11 + 11/8 - 3/8 + (-8/11)

= (-3/11 - 8/11) + (11/8 - 3/8)

= -1 + 1

= 0

d) 3/8 + (-1/4) - (7/12 - 1/6)

= 1/8 - 5/12

= -7/24

e) (1/3 + 12/67 + 13/41) - (79/67 - 28/41)

= 1/3 + 12/67 + 13/41 - 79/67 + 28/41

= 1/3 + (12/67 - 79/67) + (13/41 + 28/41)

= 1/3 - 1 + 1

= 1/3

bài 2

1,35-x=-16-(-7)

35-x=-9

x=35-(-9)=44

2,/x-2/=9 suy ra x-2=9 hoặc =-9 rồi tự tính

3, suy ra 4-2x=0 hoặc x-3 =0 tụ tính x

4, (x-2)^2=64 = 8^2 suy ra x-2 =8 hoặc -8

Bài 2: Thực hiện phép tính (tính bằng cách hợp lí nếu có thể)

-16 - (35 - x) = -7

-16 - 35 + x = -7

-51 + x = -7

x = -7 - (-51)

x = 44

lx - 2l = 9

=> \(\orbr{\begin{cases}x-2=9\\x-2=-9\end{cases}}\)

=> \(\orbr{\begin{cases}x=9+2\\x=-9+2\end{cases}}\)

=> \(\orbr{\begin{cases}x=11\\x=-7\end{cases}}\)

(4 - 2x) . (x - 3) = 0

=> \(\orbr{\begin{cases}4-2x=0\\x-3=0\end{cases}}\)

=> \(\orbr{\begin{cases}2x=4-0\\x=0+3\end{cases}}\)

=> \(\orbr{\begin{cases}2x=4\\x=3\end{cases}}\)

=> \(\orbr{\begin{cases}x=4\div2\\x=3\end{cases}}\)

=> \(\orbr{\begin{cases}x=2\\x=3\end{cases}}\)

(x - 2)² - 64 = 0

=> (x - 2)² = 0 + 64

=> (x - 2)² = 64

=> (x - 2)² = 8²

=> x - 2 = 8

=> x = 8 + 2

=> x = 10

bài 1 câu b số số hạng là : (101-2):3+1=34 tổng là : (101+2)x34:2=tự tính kết quả nhé tớ ko rành cho lắm