\(\frac{33}{2}+\frac{33}{6}+\frac{33}{18}+\frac{33}{54}+\frac{33}{162}+\frac{33}{486}\)

\(=\frac{33.3+33.3+33.3+33.3+33.3}{486}\)

\(=\frac{99.5}{486}\)

\(=\frac{495}{486}\)

Gọi \(A=\frac{33}{2}+\frac{33}{6}+...+\frac{33}{486}\)

\(A=33.\left[\left(\frac{1}{1.2}+\frac{1}{2.3}\right)+\left(\frac{1}{3.6}+\frac{1}{6.9}\right)\left(\frac{1}{9.18}+\frac{1}{18.27}\right)\right]\)

\(A=33.\left[\frac{2}{3}+\frac{2}{9}+\frac{2}{27}\right]\)

\(A=66.\left[\frac{9}{27}+\frac{3}{27}+\frac{1}{27}\right]\)

\(A=66.\frac{13}{27}\)

\(A=\frac{286}{9}\)

sai hay đúng cx ko biết nha

\(\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+\frac{2}{9.11}+\frac{2}{11.13}+\frac{2}{13.15}\)

\(=1+\frac{2}{3}-\frac{2}{3}+\frac{2}{5}-\frac{2}{5}+....+\frac{2}{15}\)

\(=1+\frac{2}{15}\)

\(=\frac{17}{15}\)

\(=\left(-\frac{5}{132}-\frac{5}{3}\right)-\left(-\frac{5}{4}+\frac{6}{11}\right)\)

\(=-\frac{75}{44}-\left(-\frac{5}{4}+\frac{6}{11}\right)\)

\(=-\frac{75}{44}+\frac{31}{44}\)

\(=-1\)

( \(\frac{-1}{4}\)+ \(\frac{7}{33}\)- \(\frac{5}{3}\) ) - ( \(\frac{-5}{4}\) + \(\frac{6}{11}\)) 

= ( \(\frac{-1}{4}\)\(\frac{-48}{33}\)) - ( \(\frac{-31}{44}\))

=  \(\frac{-1}{4}\)+ \(\frac{-48}{33}\)+ \(\frac{-31}{44}\)

= ( \(\frac{-1}{4}\)+ \(\frac{-31}{44}\)) + \(\frac{-48}{33}\)

= \(\frac{-5}{11}\) + \(\frac{-48}{33}\)

=  \(\frac{-21}{11}\)

HỌC TỐT ^^__^^

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-5}{4}+\frac{6}{11}\right)\)

\(=\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}+\frac{5}{4}-\frac{6}{11}\)

\(=\left(\frac{-1}{4}+\frac{5}{4}\right)+\left(\frac{7}{33}-\frac{6}{11}\right)-\frac{5}{3}\)

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

Cậu có thể tham khảo bài làm trên  đây ạ, chúc cậu học tốt^^

\(\frac{6+x}{33}=\frac{7}{11}\)

\(\Rightarrow\left(6+x\right)\times11=33\times7\)

     \(\left(6+x\right)\times11=231\)

    \(6+x=231\div11=21\)

\(\Rightarrow x=21-6=15\)

Vậy \(x=15\)

x=15 nhe

bằng 15

\(\frac{6+x}{33}=\frac{7}{11}\)

\(\Leftrightarrow11\cdot\left(6+x\right)=7\cdot33\)

\(\Leftrightarrow66+11x=231\)

\(\Leftrightarrow11x=231-66\)

\(\Leftrightarrow x=165:11\)

\(\Leftrightarrow x=15\)

Dấu . là dấu nhân

\(\frac{6+x}{33}=\frac{7}{11}\)

=> ( 6 + x ) . 11 = 231

=> 6 + x = 231 : 11

6 + x = 21

x = 21 - 6

x = 15

Vậy x = 15

7/11= 21/33

21/33= 6+x/33

TA CÓ: 21 = 6 + x

VẬY x = 15

CHÚC BẠN HOK TỐT NHA!

(-1/4+7/33-5/3)-(-5/12+6/11-5/42)

=-1/4+7/33-5/3-5/12-6/11+5/42

=-1/4-5/12+7/33-6/11-5/3+5/42

=-8/12+(-3/11)-25/12

=-8/12-25/12+(-3/11)

=-33/12+-3/11

=-11/4+-3/11

=-133/44

Mk làm sai rồi !

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-5}{12}+\frac{6}{11}-\frac{5}{42}\right)\)

\(=\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}+\frac{5}{12}-\frac{6}{11}+\frac{5}{42}\)

\(=\left(\frac{5}{12}-\frac{1}{4}\right)-\left(\frac{5}{3}-\frac{5}{42}\right)-\left(\frac{6}{11}-\frac{7}{33}\right)\)

\(=\frac{1}{6}-\frac{65}{42}-\frac{1}{3}\)

\(=\frac{-29}{21}-\frac{1}{3}\)

\(=\frac{-12}{7}\)

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-5}{12}+\frac{6}{11}-\frac{5}{42}\right)\)

\(=-\frac{1}{4}+\frac{7}{33}-\frac{5}{3}+\frac{5}{12}-\frac{6}{11}+\frac{5}{42}\)

\(=\frac{5-3}{12}+\frac{7-18}{33}+\frac{5+70}{42}=\frac{1}{6}-\frac{1}{3}+\frac{65}{42}\)

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-15}{12}+\frac{6}{11}-\frac{48}{49}\right)\)

\(=\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}+\frac{15}{12}-\frac{6}{11}+\frac{48}{49}\)

\(=\left(\frac{-1}{4}-\frac{5}{3}+\frac{15}{12}\right)+\left(\frac{7}{33}-\frac{6}{11}\right)+\frac{48}{49}\)

\(=\left(\frac{-3}{12}-\frac{20}{12}+\frac{15}{12}\right)+\left(\frac{7}{33}-\frac{18}{33}\right)+\frac{48}{49}\)

\(=\left(\frac{-23}{12}+\frac{15}{12}\right)+\left(\frac{-11}{33}\right)+\frac{48}{49}\)

\(=\frac{-2}{3}+\left(\frac{-1}{3}\right)+\frac{48}{49}\)

\(=-1+\frac{48}{49}\)

\(=-\frac{1}{49}\)

Ùng hộ mk nha ^_-

giúp mình với, mình cần gấp lắm lun

giải được chưa, mình giải cho :v

cậu làm được không?

\(\frac{x+6}{33}=\frac{7}{11}\)

33 :3=11

x+6:3=7

7 x 3=21

21-6=15

Vậy\(\frac{15+6}{33}=\frac{7}{11}\)

\(X+6=\frac{7.33}{11}\)

\(X+6=21\)

\(X=21-6\)

\(X=5\)