Cho mình hỏi:
-2/5x+1/5=3/10 và
0,5x-2/3=7/12
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TB
19 tháng 2 2022
a) 1/7 + 2/7 + 3/7 + 4/7 + 5/7 +6/7 = 3
b) 1/2 + 2/4 + 3/6 + 4/8 + 5/10 + 6/12 = 3
CH
1
25 tháng 4 2019
\(\frac{-2}{5}x+\frac{1}{5}=\frac{3}{10}\)
\(\Leftrightarrow\frac{-2}{5}x=\frac{3}{10}-\frac{1}{5}=\frac{1}{10}\)
\(\Leftrightarrow x=\frac{1}{10}:\frac{-2}{5}=\frac{1}{10}.\frac{5}{-2}=\frac{1}{-4}\)
Vậy: x=1/-4
\(0,5x-\frac{2}{3}=\frac{7}{12}\)
\(\Leftrightarrow\frac{1}{2}x=\frac{7}{12}+\frac{2}{3}\)
\(\Leftrightarrow\frac{1}{2}x=\frac{15}{12}=\frac{5}{4}\)
\(\Leftrightarrow x=\frac{5}{4}:\frac{1}{2}=\frac{5}{4}.2=\frac{5}{2}\)
Vậy x=5/2
11 tháng 8 2023
\(=\dfrac{3}{2}-\dfrac{2}{21}-\dfrac{7}{12}+\left[\dfrac{15}{21}-\dfrac{1}{3}+\dfrac{5}{4}-\dfrac{2}{7}-\dfrac{1}{3}\right]\)
=11/12-2/21+5/7-2/3+5/4-2/7
=11/12-2/3+5/4-2/21+3/7
=11/12-8/12+15/12-2/21+9/21
=18/12+7/21
=3/2+1/3
=9/6+2/6=11/6
NA
Nguyễn An Ninh
VIP
14 tháng 8 2023
\(B=\dfrac{3}{2}-\dfrac{2}{21}-\left\{\dfrac{7}{12}-\left[\dfrac{15}{21}-\left(\dfrac{1}{3}-\dfrac{5}{4}\right)-\left(\dfrac{2}{7}+\dfrac{1}{3}\right)\right]\right\}\)
\(B=\dfrac{3}{2}-\dfrac{2}{21}-\left\{\dfrac{7}{12}-\left[\dfrac{15}{21}-\left(-\dfrac{11}{12}\right)-\dfrac{13}{21}\right]\right\}\)
\(B=\dfrac{3}{2}-\dfrac{2}{21}-\left\{\dfrac{7}{12}-\dfrac{85}{84}\right\}\)
\(B=\dfrac{3}{2}-\dfrac{2}{21}-\left(-\dfrac{3}{7}\right)\)
\(B=\dfrac{11}{6}\)
VT
2 tháng 3 2023
\(\left(6:3,5-1\dfrac{1}{6}\times\dfrac{6}{7}\right):\left(4,2\times\dfrac{10}{11}+5\dfrac{2}{11}\right)\\ =\left(\dfrac{12}{7}-\dfrac{7}{6}\times\dfrac{6}{7}\right):\left(\dfrac{21}{5}\times\dfrac{10}{11}+\dfrac{57}{11}\right)\\ =\left(\dfrac{17}{7}-1\right):\left(\dfrac{42}{11}+\dfrac{57}{11}\right)\\ =\dfrac{10}{7}:9\\ =\dfrac{10}{63}\)
NK
2 tháng 3 2023
\(\left(6:\dfrac{3}{5}-1\dfrac{1}{6}\times\dfrac{6}{7}\right):\left(4,2\times\dfrac{10}{11}+5\dfrac{2}{11}\right)\)
\(=\left(6\times\dfrac{5}{3}-\dfrac{7}{6}\times\dfrac{6}{7}\right):\left(\dfrac{21}{5}\times\dfrac{10}{11}+\dfrac{57}{11}\right)\)
\(=\left(10-1\right):\left(\dfrac{42}{11}+\dfrac{57}{11}\right)=9:9=1\)
a, \(\frac{-2}{5x}\) +\(\frac{1}{5}\) =\(\frac{3}{10}\)
⇒\(\frac{-4}{10x}\) +\(\frac{2x}{10x}\) =\(\frac{3x}{10x}\)
⇒-4 +2x=3x
⇒x=-4
b, 0,5x-\(\frac{2}{3}\)=\(\frac{7}{12}\)
⇒\(\frac{x}{2}\) -\(\frac{2}{3}\)=\(\frac{7}{12}\)
⇒\(\frac{6x}{12}\) -\(\frac{8}{12}\) =\(\frac{7}{12}\)
⇒6x-8=7
⇒6x=15
⇒x=\(\frac{15}{6}\)