=11/2(-1/5+3/7-4/5+4/7)

=11/2(1-1)

=0

\(\left(\dfrac{-1}{5}+\dfrac{3}{7}\right):\dfrac{2}{11}+\left(\dfrac{-4}{5}+\dfrac{4}{7}\right):\dfrac{2}{11}\) 

\(=\dfrac{8}{35}:\dfrac{2}{11}+\dfrac{-8}{35}:\dfrac{2}{11}\) 

\(=\dfrac{2}{11}:\left(\dfrac{8}{35}+\dfrac{-8}{35}\right)\) 

\(=\dfrac{2}{11}:0=0\) 

Cảm ơn bạn nha

s bạn lại cảm ơn mik?

Nhiwf bạn nên mình làm được bài này ! Hihi 

\(\frac{3.7.8.13}{14\cdot15\cdot26}=\frac{3\cdot7\cdot8\cdot13}{2\cdot7\cdot3\cdot5\cdot2\cdot13}=\frac{8}{5\cdot2\cdot2}=\frac{8}{20}=\frac{2}{5}\)

\(\frac{3.7.8.13}{14.15.26}=\frac{3.7.2^3.13}{2.7.3.5.13.2}=\frac{1.7.2.1}{1.1.1.5.1.1}=\frac{14}{5}\)

\(\frac{11.8-11.3}{17-6}=\frac{11.\left(8-3\right)}{11}=\frac{11.5}{11}=\frac{1.5}{1}=\frac{5}{1}=5\)

\(\frac{-17.13+17.2}{11.2-11.9}=\frac{-17.13+\left(-17\right).2}{11.\left(2-9\right)}=\frac{-17.\left(-13+2\right)}{11.\left(-7\right)}=\frac{-17.\left(-11\right)}{11.\left(-7\right)}=\frac{-17.\left(-1\right)}{-1.\left(-7\right)}=\frac{17}{7}\)

\(\frac{7}{9.10^2-2.10^2}=\frac{7}{100\left(9-2\right)}=\frac{7}{100.7}=\frac{7}{700}=\frac{1}{100}\)

mình làm được tới đó thôi, hihi. 

Co ai biết lam con thu 5 ko, giúp minh voi. Dang mai minh nộp bai roi

`1/10x+1/15(11-x)=1`

`<=>1/10x+11/15-1/15x=1`

`<=>1/30x=1-11/15=4/15`

`<=>x=4/15*30=8`

Vậy `x=8`

\(\dfrac{x}{10}+\dfrac{11-x}{15}=1< =>\dfrac{3x+22-2x}{30}=1\)

\(< =>\dfrac{3x+22-2x}{30}=1=>x+22=30< =>x=30-22< =>x=8\)

Chọn B

c: =1/3(14*10-10)

=130*1/3=130/3

\(3\cdot3^{10}=3^{1+10}=3^{11}\)

\(3\cdot3^{10}=3^{1+10}=3^{11}\)

Theo nhân hai luỹ thừa cùng cơ số: 

Ta có: \(a^m\cdot a^n=a^{m+n}\)