\(a,\dfrac{6}{11}+6+\dfrac{5}{7}=\dfrac{42+462+55}{77}=\dfrac{559}{77}\)

\(b,\dfrac{9}{8}\times\dfrac{3}{12}:\dfrac{5}{9}=\dfrac{9}{8}\times\dfrac{3}{12}\times\dfrac{9}{5}=\dfrac{243}{480}=\dfrac{81}{160}\)

\(c,\dfrac{8}{7}:4+2=\dfrac{8}{7}\times\dfrac{1}{4}+2=\dfrac{8}{28}+2=\dfrac{2}{7}+2=\dfrac{16}{7}\)

\(d,\dfrac{3}{5}+4:\dfrac{6}{4}=\dfrac{3}{5}+4\times\dfrac{4}{6}=\dfrac{3}{5}+\dfrac{8}{3}=\dfrac{49}{15}\)

\(a,\dfrac{6}{11}+6+\dfrac{5}{7}=\dfrac{6}{11}+\dfrac{66}{11}+\dfrac{5}{7}=\dfrac{72}{11}+\dfrac{5}{7}=\dfrac{504}{77}+\dfrac{55}{77}=\dfrac{559}{77}\)

\(b,\dfrac{9}{8}\times\dfrac{3}{12}:\dfrac{5}{9}=\dfrac{9}{32}:\dfrac{5}{9}=\dfrac{9}{32}\times\dfrac{9}{5}=\dfrac{81}{160}\)

\(c,\dfrac{8}{7}:4+2=\dfrac{8}{7}\times\dfrac{1}{4}+2=\dfrac{2}{7}+2=\dfrac{2}{7}+\dfrac{14}{7}=\dfrac{16}{7}\)

\(d,\dfrac{3}{5}+4:\dfrac{6}{4}=\dfrac{3}{5}+4\times\dfrac{4}{6}=\dfrac{3}{5}+\dfrac{8}{3}=\dfrac{9}{15}+\dfrac{40}{15}=\dfrac{49}{15}\)

Ta có: \(\left(x-3\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+9\left(x+1\right)^2=15\)

\(\Leftrightarrow x^3-9x^2+27x-27-x^3+27+9\left(x^2+2x+1\right)=15\)

\(\Leftrightarrow-9x^2+27x+9x^2+18x+9=15\)

\(\Leftrightarrow45x=6\)

hay \(x=\dfrac{2}{15}\)

Giải cách phương trình sau

2.(x+3/5)=5-(13/5+x)

=> 2x + 6/5 = 5 - 13/5 - x

=> 2x + x = 12/5 - 6/5

=> 3x = 6/5

=> x = 2/5

\(3\left(x-2\right)^2+9\left(x-1\right)=3\left(x^2+x-3\right)\\ \Leftrightarrow3\left(x^2-4x+4\right)+9x-9=3x^2+3x-9\\ \Leftrightarrow3x^2-12x+12+9x-9-3x^2-3x+9=0\\ \Leftrightarrow-6x+12=0\\ \Leftrightarrow x=2\)

\(3\left(x-2\right)^2+9\left(x-1\right)=3\left(x^2+x-3\right)\)

\(\Leftrightarrow3\left(x^2-4x+4\right)+9x-9=3x^2+3x-9\)

\(\Leftrightarrow3x^2-12x+12+9x-9-3x^2-2x+9=0\)

\(\Leftrightarrow-6x-6=0\)

\(\Leftrightarrow-6\left(x+1\right)=0\)

\(\Leftrightarrow x+1=0\)

\(\Leftrightarrow x=-1\)

Vậy phương trình có nghiệm là \(-1\)

Bài 2: 

Ta có: \(16x+40=10\cdot3^2+5\left(1+2+3\right)\)

\(\Leftrightarrow16x+40=90+30\)

\(\Leftrightarrow16x=80\)

hay x=5

Bài 1 :

[( 35 - 5 ) : 3 ]³ + 3

= [30 : 3]³ + 3

= 10³ + 3

= 1000 + 3

= 1003

Đây nha bạn!!!

Chúc bạn học tốt!!!

Câu này dễ quá

        \(\dfrac{5}{6}\) + \(\dfrac{7}{8}\)

=     \(\dfrac{5\times4}{6\times4}\) + \(\dfrac{7\times3}{8\times3}\)

=      \(\dfrac{20}{24}\) + \(\dfrac{21}{24}\)

=         \(\dfrac{41}{24}\)

5/6 + 7/8 = 41/24

2 + 2/3 = 8/3

7/9 - 1/7 = 40/63

1-1/11 =10/11

2x17/81 = 34/81

9/11 : 5/6 = 54/55

3: 12/25 = 25/4

                Tick cho mik nhé.

       Chúc bạn học tốt nha !

2 + \(\dfrac{2}{3}\)

= \(\dfrac{2\times3}{1\times3}\) +  \(\dfrac{2}{3}\)

= \(\dfrac{6}{3}\) + \(\dfrac{2}{3}\)

= \(\dfrac{8}{3}\)

\(\frac{2^{20}.9^3+15.4^9.81^2}{6^8.2^{11}+12^{10}}\)

\(=\frac{2^{20}.3^6+5.2^{18}.3^9}{2^{19}.3^8+2^{20}.3^{10}}\)

\(=\frac{2^{18}.3^6.\left(2^2+5.3^3\right)}{2^{19}.3^8.\left(1+2.3^2\right)}=\frac{139}{2.3^2.19}=\frac{139}{342}\)

CÔNG CHÚA ORI bạn có thể ghi bước trung gian đoạn cuối giúp mk đc ko??? Mk ko hỉu cho lắm

\(\frac{2^{20}.9^3+15.4^9.81^2}{6^8.2^{11}+12^{10}}\)

\(=\frac{2^{20}.3^6+3.5.2^{18}.3^8}{2^8.3^8.2^{11}+4^{10}.3^{10}}\)

\(=\frac{2^{20}.3^6+2^{18}.3^9.5}{2^{19}.3^8+2^{20}.3^{10}}\)

\(=\frac{2^{18}.3^6\left(2^2+3^3.5\right)}{2^{19}.3^8\left(1+2.3^2\right)}\)

\(=\frac{4+27.5}{2.3^2\left(1+18\right)}\)

\(=\frac{4+135}{18.19}\)

\(=\frac{139}{342}\)