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4 tháng 6 2016
Tìm x, biết:
3(x+2)(x+5) +5(x+5)(x+10) +7(x+10)(x+17) =x(x+2)(x+17) (x∉−2;−5;−10;−17)
2(x−1)(x−3) +5(x−3)(x−8) +12(x−8)(x−20) −1x−20 =−34 (x∉1;3;8;20)
x+110 +2+111 x+112 =x+113 +x+114
x−1030 +x−1443 +x−595 +x−1488 =0
25 tháng 3 2017
a) = -3/7 . 5/11 + -3/7 . 6/11 + 9/7
= -3/7. ( 5/11 + 6/11 ) + 9/7
= -3/7. 1 + 9/7
= -3/7 + 9/7
= 6/7
b) = 4/13 + 9/13 + -11/5 + 6/5 - 3/4
= 13/13 + -5/5 - 3/4
= 1 + (-1) - 3/4
= 0 - 3/4
= -3/4
c) = -19/17. 4/7 + 19/17. -3/7 + 19/17
= 19/17. -4/7 + 19/17. -3/7 + 19/17.1
= 19/17.( -4/7 + -3/7 + 19/17
= 19/17. -7/7 + 19/17
= 19/17. (-1) + 19/17
= -19/17 + 19/17
= 0
tk mk nha,thanks
29 tháng 5 2017
a) \(5\frac{8}{17}:x+\frac{-1}{17}:x+3\frac{1}{17}:17\frac{1}{3}=\frac{4}{17}\)
\(\frac{93}{17}:x+\frac{-1}{17}:x+\frac{52}{17}:\frac{52}{3}=\frac{4}{17}\)
\(\left(\frac{93}{17}+\frac{-1}{17}\right):x+\frac{52}{17}.\frac{3}{52}=\frac{4}{17}\)
\(\frac{92}{17}:x+\frac{3}{17}=\frac{4}{17}\)
\(\frac{92}{17}:x=\frac{4}{17}-\frac{3}{17}\)
\(\frac{92}{17}:x=\frac{1}{17}\)
\(x=\frac{92}{17}:\frac{1}{17}\)
\(x=92\)
b) \(\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{x.\left(x+3\right)}=\frac{6}{19}\)
\(\frac{1}{3}.\left(1-\frac{1}{4}\right)+\frac{1}{3}.\left(\frac{1}{4}-\frac{1}{7}\right)+\frac{1}{3}.\left(\frac{1}{7}-\frac{1}{10}\right)+...+\frac{1}{3}.\left(\frac{1}{x}-\frac{1}{x+3}\right)=\frac{6}{19}\)
\(\frac{1}{3}.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{x}-\frac{1}{x+3}\right)=\frac{6}{19}\)
\(\frac{1}{3}.\left(1-\frac{1}{x+3}\right)=\frac{6}{19}\)
\(1-\frac{1}{x+3}=\frac{6}{19}:\frac{1}{3}\)
\(1-\frac{1}{x+3}=\frac{18}{19}\)
\(\frac{1}{x+3}=1-\frac{18}{19}\)
\(\frac{1}{x+3}=\frac{1}{19}\)
\(\Rightarrow x+3=19\)
\(\Rightarrow x=19-3\)
\(\Rightarrow x=16\)
5 tháng 7 2019
\(\frac{5}{17}\left(3\frac{1}{7}+8\frac{7}{3}\right)\frac{15}{17}\left(3\frac{7}{6}+8\frac{1}{7}\right)=\frac{5}{17}\left(\frac{22}{7}+\frac{31}{3}\right)\frac{15}{17}\left(\frac{25}{6}+\frac{57}{7}\right)\)
\(=\frac{5}{17}.\frac{283}{21}.\frac{15}{17}.\frac{517}{42}=\frac{10973325}{254898}=\frac{3657775}{84966}\)
\(\frac{43}{20}+\frac{17}{6}:\left[\frac{5}{8}+\frac{7}{30}\right]\)
= \(\frac{43}{20}+\frac{17}{6}:\frac{103}{120}\)
= \(\frac{43}{20}+\frac{340}{103}\)
=\(\frac{11229}{2060}\).
\(\frac{43}{20}+\frac{17}{6}:\left[\frac{5}{8}+\frac{7}{30}\right]\)
\(=\frac{43}{20}+\frac{17}{6}:\left[\frac{103}{120}\right]\)
\(=\frac{43}{20}+\frac{340}{103}=\frac{11229}{2060}\)