a) \(\frac{1}{12}+\frac{3}{15}+\frac{11}{12}+\frac{1}{71}-\frac{12}{10}=\left(\frac{1}{12}+\frac{11}{12}\right)+\left(\frac{1}{5}-\frac{1}{5}\right)+\frac{1}{71}\)

\(=\frac{12}{12}+0+\frac{1}{71}=1+\frac{1}{71}=1\frac{1}{71}=\frac{72}{71}\)

b) \(\frac{2}{3}-4\left(\frac{1}{2}+\frac{3}{4}\right)=\frac{2}{3}-4.\frac{5}{4}=\frac{2}{3}-5=\frac{2}{3}-\frac{15}{3}=-\frac{13}{3}\)

c) \(\frac{-4}{13}.\frac{3}{17}+\frac{-12}{13}.\frac{4}{7}+\frac{4}{13}=\frac{4}{13}.\frac{-3}{17}+\frac{4}{13}.\frac{-12}{17}+\frac{4}{13}.1\)

\(=\frac{4}{13}\left(\frac{-3}{17}+\frac{-12}{17}+1\right)=\frac{4}{13}\left(\frac{-15}{17}+\frac{17}{17}\right)=\frac{4}{13}.\frac{2}{17}=\frac{8}{221}\)

d) \(\frac{10^3+2.5+5^3}{55}=\frac{1000+10+125}{55}=\frac{1135}{55}=\frac{227}{11}\)

\(\left(\frac{1}{3}-\frac{1}{4}\right)x+\frac{9}{13}:1\frac{2}{13}=\frac{1}{12}\)

\(\left(\frac{4}{12}-\frac{3}{12}\right)x+\frac{9}{13}:\frac{15}{13}=\frac{1}{12}\)

\(\left(-\frac{1}{12}\right)x+\frac{9}{13}.\frac{13}{15}=\frac{1}{12}\)

\(\left(-\frac{1}{12}\right)x+\frac{3}{5}=\frac{1}{12}\)

\(\left(-\frac{1}{2}\right)x=\frac{1}{12}-\frac{3}{5}\)

\(\left(-\frac{1}{12}\right)x=\frac{5}{60}-\frac{36}{60}\)

\(\left(-\frac{1}{12}\right)x=-\frac{31}{60}\)

\(x=-\frac{31}{60}:\left(-\frac{1}{12}\right)\)

\(x=-\frac{31}{60}.\frac{12}{-1}\)

\(\Rightarrow x=\frac{-31}{-5}\)

\(\Rightarrow x=\frac{31}{5}\)

\(\left|x-12\right|^{12}-\left|x-13\right|^{13}=1\)

\(\Rightarrow x=13\)

Các câu dễ tự làm :v

\(\dfrac{x+1}{10}+\dfrac{x+1}{11}+\dfrac{x+1}{12}=\dfrac{x+1}{13}+\dfrac{x+1}{14}\)

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

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

\(\Rightarrow x+1=0\Rightarrow x=-1\)

\(\dfrac{x+4}{2000}+\dfrac{x+3}{2001}=\dfrac{x+2}{2002}+\dfrac{x+1}{2003}\)

\(\Rightarrow\dfrac{x+4}{2000}+1+\dfrac{x+3}{2001}+1=\dfrac{x+2}{2002}+1+\dfrac{x+1}{2003}+1\)

\(\Rightarrow\dfrac{x+2004}{2000}+\dfrac{x+2004}{2001}=\dfrac{x+2004}{2002}+\dfrac{x+2004}{2003}\)

\(\Rightarrow\dfrac{x+2004}{2000}+\dfrac{x+2004}{2001}-\dfrac{x+2004}{2002}-\dfrac{x+2004}{2003}=0\)

\(\Rightarrow\left(x+2004\right)\left(\dfrac{1}{2000}+\dfrac{1}{2001}-\dfrac{1}{2002}-\dfrac{1}{2003}\right)=0\)

\(\Rightarrow x+2004=0\Rightarrow x=-2004\)

bạn học tới bài này cs đề là j z

7 hằng đẳng thức nha cậu

\(\frac{-12}{13}\)x-5=\(\frac{79}{13}\)

\(\frac{-12}{13}\)x=\(\frac{79}{13}\)+5=\(\frac{144}{13}\)

x=\(\frac{144}{13}\)\(\div\)\(\frac{-12}{13}\)=-12

-12/13.x-5=6.1/13

-12/13.x-5=6/13

x-5=-1/2

x=-1/2+5

x=9/2

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