a,\(\frac{11}{12}-\left(\frac{5}{42}-x\right)=\frac{15}{28}-\frac{11}{12}\)

\(\Leftrightarrow\frac{11}{12}-\frac{5}{42}+x=\frac{15}{28}-\frac{11}{12}\)

\(\Leftrightarrow x=\frac{15}{28}-\frac{11}{12}-\frac{11}{12}+\frac{5}{42}\)

\(\Leftrightarrow x=\left(\frac{15}{28}+\frac{5}{42}\right)-\left(\frac{11}{12}+\frac{11}{12}\right)\)

\(\Leftrightarrow x=\frac{55}{84}-\frac{11}{6}\)

\(\Leftrightarrow x=\frac{-33}{28}\)

b, \(\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}=\frac{x+1}{13}+\frac{x+1}{14}\)

\(\Leftrightarrow\frac{x+1}{10}+\frac{x+1}{11}+\frac{x+1}{12}-\frac{x+1}{13}-\frac{x+1}{14}=0\)

\(\Leftrightarrow\left(x+1\right)\left(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)

\(\Leftrightarrow x+1=0\)

\(\Leftrightarrow x=-1\)

a) 0,2 x 317 x 7 + 0,14 x 3520 + 33,1 x 14

= ( 0,2 x 7 ) x 317 + 0,14 x 3520 + 33,1 x 14

= 1,4 x 317 + 0,14 x 3520 + 33,1 x 14 

=   443,8 + 492,8 + 463,4

= 1400

b) 2 + 5 + 8 + ... + 65 - 387: từ 2 đến 65 có 22 số hạng

= { ( 65 + 2 ) x 22 : 2 } - 387

=  737 - 387

= 350

0,2*317*7+0,14*3520+33,1*14

=(0,2*7)*317+0,14*10*352+33,1*10*1,4

=1,4*317+1,4*352+331*1,4

=1,4*(317+352+331)

=1,4*1000

=1400

b)737-387=350

0,2 * 317 * 7 +  0,14 * 3520+33,1 * 14

=(0,2*7)*10*31,7 + 0,14*100*35,2+33,1*14

=1,4*10*31,7 + 14*35,2 + 33,1*14

=14*31,7+14*35,2+33,1*14

=14*(31,7+35,2+33,1)

=14*100=1400

x+32/11 + x+23/12 = x+38/13 + x+27/14

\(\Rightarrow\frac{x+32}{11}-3+\frac{x+23}{12}-2=\frac{x+38}{13}-3+\frac{x+27}{14}-2\)

\(\Rightarrow\frac{x-1}{11}+\frac{x-1}{12}=\frac{x-1}{13}+\frac{x-1}{14}\)

\(\Rightarrow\frac{x-1}{11}+\frac{x-1}{12}-\frac{x-1}{13}-\frac{x-1}{14}=0\)

\(\Rightarrow\left(x-1\right)\left(\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\right)=0\)

\(\Rightarrow x-1=0\).Do \(\frac{1}{11}+\frac{1}{12}-\frac{1}{13}-\frac{1}{14}\ne0\)

\(\Rightarrow x=1\)

Mik thấy câu a sai sao ý,

ko có kết quả sao tìm x

cho mik xin lỗi nha

\(\left(19x+2.5^2\right):14=\left(13-8\right)^2-4^2\)

\(\Leftrightarrow\left(19x+50\right):14=5^2-4^2\)

\(\Leftrightarrow\frac{19}{14}x+\frac{25}{7}=9\)

\(\Leftrightarrow\frac{19}{14}x=\frac{38}{7}\)

\(\Leftrightarrow x=4\)

đưa câu kahcs đi bạn

ban oi minh biet dap so thoi 

mấy bạn làm ơn ghi kết quả giúp mình với, nếu ko bik cách giải thì mí abnj ghi kết quả cũng đc

a) \(\left(\frac{4}{13}.\frac{6}{5}+\frac{4}{13}.\frac{2}{5}\right).\left(2x+1\right)^2=\frac{10}{13}\)

\(\left(\frac{4}{13}.\frac{8}{5}\right).\left(2x+1\right)^2=\frac{10}{13}\)

\(\frac{32}{65}.\left(2x+1\right)^2=\frac{10}{13}\)

\(\left(2x+1\right)^2=\frac{10}{13}\div\frac{32}{65}\)

\(\left(2x+1\right)^2=\frac{25}{16}\)

\(\Rightarrow2x+1\in\left\{\frac{5}{4};-\frac{5}{4}\right\}\)

\(\hept{\begin{cases}2x+1=\frac{5}{4}\\2x+1=-\frac{5}{4}\end{cases}\Rightarrow\hept{\begin{cases}2x=\frac{1}{4}\\2x=-\frac{9}{4}\end{cases}\Rightarrow}\hept{\begin{cases}x=\frac{1}{8}\\x=-\frac{9}{8}\end{cases}}}\)

Vậy \(x\in\left\{\frac{1}{8};-\frac{9}{8}\right\}\)

\(x^3-\frac{9}{16}.x=0\)

\(x\left(x^2-\frac{9}{16}\right)=0\)

\(\hept{\begin{cases}x=0\\x^2-\frac{9}{16}=0\end{cases}\Rightarrow\hept{\begin{cases}x=0\\x^2=\frac{9}{16}\end{cases}\Rightarrow}\hept{\begin{cases}x=0\\x=\pm\frac{3}{4}\end{cases}}}\)

Vậy \(x\in\left\{0;\frac{3}{4};-\frac{3}{4}\right\}\)