Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Ta có : \(\frac{x-1}{65}+\frac{x-3}{63}=\frac{x-5}{61}=\frac{x-7}{59}\)
\(\Leftrightarrow\left(\frac{x-1}{65}-1\right)+\left(\frac{x-3}{63}-1\right)=\left(\frac{x-5}{61}-1\right)+\left(\frac{x-7}{59}-1\right)\)
\(\Leftrightarrow\frac{x-66}{65}+\frac{x-66}{63}=\frac{x-66}{61}+\frac{x-66}{59}\)
\(\Leftrightarrow\frac{x-66}{65}+\frac{x-66}{63}-\frac{x-66}{61}-\frac{x-66}{59}=0\)
\(\Leftrightarrow\left(x-66\right)\left(\frac{1}{65}+\frac{1}{63}-\frac{1}{61}-\frac{1}{59}\right)=0\)
Mà ; \(\left(\frac{1}{65}+\frac{1}{63}-\frac{1}{61}-\frac{1}{59}\right)\ne0\)
Nên x - 66 = 0
=> x = 66
a ) \(\frac{15}{2}-\left(-\frac{7}{3}\right)-\frac{7}{3}-10\)
= \(\frac{15}{2}+\frac{7}{3}-\frac{7}{3}-10\)
=\(\frac{15}{2}-10\)
= \(\frac{-5}{2}\)
b ) \(\frac{65}{2}+\left(-\frac{65}{3}\right)-\frac{130}{3}\)
= \(\frac{65}{6}-\frac{130}{3}\)
=\(\frac{-65}{2}\)
c ) \(\left(\frac{-16}{3}\right)+\left(\frac{-2}{3}\right)\)
= -6
d ) \(\frac{1}{7}+\frac{9}{-8}+\left(-\frac{3}{14}\right)\)
= \(\frac{-55}{56}+\left(-\frac{3}{14}\right)\)
= \(\frac{-67}{56}\)
e ) - 1,8 +\(\frac{5}{-6}\)
= \(\frac{-79}{30}\)
\(A=17\left(\frac{2}{7\cdot13}+\frac{3}{13\cdot22}+\frac{5}{22\cdot37}+\frac{4}{37\cdot49}\right)\)
\(=\frac{17}{3}\left(\frac{6}{7\cdot13}+\frac{9}{13\cdot22}+\frac{15}{22\cdot37}+\frac{12}{37\cdot49}\right)\)
\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{13}+\frac{1}{13}-\frac{1}{22}+\frac{1}{22}-\frac{1}{37}+\frac{1}{37}-\frac{1}{49}\right)\)
\(=\frac{17}{3}\left(\frac{1}{7}-\frac{1}{49}\right)\)
\(B=13\left(\frac{3}{7\cdot16}+\frac{5}{16\cdot31}+\frac{4}{31\cdot43}+\frac{2}{43\cdot49}\right)\)
\(=\frac{13}{3}\left(\frac{9}{7\cdot16}+\frac{15}{16\cdot31}+\frac{12}{31\cdot43}+\frac{6}{43\cdot49}\right)\)
\(=\frac{13}{3}\left(\frac{1}{7}-\frac{1}{16}+\frac{1}{16}-\frac{1}{31}+\frac{1}{31}-\frac{1}{43}+\frac{1}{43}-\frac{1}{49}\right)\)
\(=\frac{13}{3}\left(\frac{1}{7}-\frac{1}{49}\right)\)
\(\Rightarrow\frac{A}{B}=\frac{\frac{17}{3}\left(\frac{1}{7}-\frac{1}{49}\right)}{\frac{13}{3}\left(\frac{1}{7}-\frac{1}{49}\right)}\)\(=\frac{\frac{17}{3}}{\frac{13}{3}}=\frac{17}{13}\)
a ) \(\frac{15}{2}-\left(-\frac{7}{3}\right)-\frac{7}{3}-10\)
= \(\frac{15}{2}+\frac{7}{3}-\frac{7}{3}-10\)
=\(\frac{15}{2}-10\)
= \(\frac{-5}{2}\)
b ) \(\frac{65}{2}+\left(-\frac{65}{3}\right)-\frac{130}{3}\)
= \(\frac{65}{6}-\frac{130}{3}\)
=\(\frac{-65}{2}\)
c ) \(\left(\frac{-16}{3}\right)+\left(\frac{-2}{3}\right)\)
= -6
d ) \(\frac{1}{7}+\frac{9}{-8}+\left(-\frac{3}{14}\right)\)
= \(\frac{-55}{56}+\left(-\frac{3}{14}\right)\)
= \(\frac{-67}{56}\)
e ) - 1,8 +\(\frac{5}{-6}\)
= \(\frac{-79}{30}\)
Bài làm
\(C=-\frac{3}{5}.\frac{20}{135}.\frac{-7}{1400}.\frac{250}{3}.\frac{27}{10}\)
\(C=\frac{-3}{5}.\frac{4}{27}.\frac{-1}{200}.\frac{250}{3}.\frac{27}{10}\)
\(C=\frac{-3.4.\left(-1\right).250.27}{5.27.200.3.10}\)
\(C=\frac{1}{10}\)
Vậy \(C=\frac{1}{10}\)
# Học tốt #
C = \(\frac{-3}{5}\cdot\frac{20}{135}\cdot\frac{-7}{1400}\cdot\frac{250}{3}\cdot\frac{27}{10}\) C = \(\left(\frac{-3}{5}\cdot\frac{250}{3}\right)\cdot\left(\frac{20}{135}\cdot\frac{27}{10}\right)\cdot\frac{-7}{1400}\) C = \(-50\cdot\frac{2}{5}\cdot\frac{-7}{1400}\) C = \(-20\cdot\frac{-7}{1400}\) C = \(\frac{1}{10}\)