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Q
25 tháng 6 2017
1) \(x+\dfrac{30}{100}x=-1,31\)
\(\Leftrightarrow x+\dfrac{3}{10}x=-\dfrac{131}{100}\)
\(\Leftrightarrow100x+30x=-131\)
\(\Leftrightarrow130x=-131\)
\(\Leftrightarrow x=-\dfrac{131}{130}\)
Vậy \(x=-\dfrac{131}{130}\)
b) \(\left(4,5-2x\right)\cdot\left(-1\dfrac{4}{7}\right)=\dfrac{11}{4}\)
\(\Leftrightarrow\left(\dfrac{9}{2}-2x\right)\cdot\left(-\dfrac{4}{7}\right)=\dfrac{11}{4}\)
\(\Leftrightarrow-\dfrac{18}{7}+\dfrac{8}{7}x=\dfrac{11}{4}\)
\(\Leftrightarrow-72+32x=77\)
\(\Leftrightarrow32x=77+72\)
\(\Leftrightarrow32x=149\)
\(\Leftrightarrow x=\dfrac{149}{32}\)
Vậy \(x=\dfrac{149}{32}\)
VT
1
26 tháng 6 2022
=>3/10(x-5)=2x+5
=>3/10x-3/2=2x+5
=>-17/10x=5+3/2=6/2+3/2=11/2
=>x=-55/17
29 tháng 6 2022
\(\Leftrightarrow\left(x-5\right)\cdot\dfrac{3}{10}=\dfrac{x}{5}+5\)
=>3/10x-3/2=1/5x+5
=>1/10x=5+3/2=10/2+3/2=13/2
=>x=13/2:1/10=13/2x10=65
25 tháng 3 2017
x + \(\frac{3}{10}\)x - -1,31
x . ( \(1\)+ \(\frac{3}{10}\)) = -1,31
x . \(\frac{13}{10}\)= -1,31
x = -1,31 : \(\frac{13}{10}\)
x = \(\frac{-131}{130}\)
ai tốt bụng thì tk cho mk nha, mk đg âm điểm nè
29 tháng 4 2018
\(x+30\%x=-1,31\\ x+\dfrac{3}{10}x=-1\dfrac{31}{100}\\ x\cdot\left(1+\dfrac{3}{10}\right)=-\dfrac{131}{100}\\ x\cdot\dfrac{13}{10}=-\dfrac{131}{100}\\ x=-\dfrac{131}{100}:\dfrac{13}{10}=\dfrac{-131}{100}\cdot\dfrac{10}{13}=-\dfrac{131}{130}\)
26 tháng 3 2017
1.
\(\dfrac{30}{100}.x+\dfrac{1}{4}=\dfrac{1}{5}.x-\dfrac{1}{2}\)
\(\dfrac{3}{10}.x=\dfrac{1}{5}.x-\dfrac{1}{2}-\dfrac{1}{4}\)
\(\dfrac{3}{10}.x=\dfrac{1}{5}.x-\dfrac{1}{4}\)
\(\dfrac{1}{5}.x-\dfrac{3}{10}.x=\dfrac{1}{4}\)
\(\left(\dfrac{1}{5}-\dfrac{3}{10}\right).x=\dfrac{1}{4}\)
\(\dfrac{-1}{10}.x=\dfrac{1}{4}\)
\(x=\dfrac{1}{4}:\dfrac{-1}{10}\)
x=\(\dfrac{5}{-2}\)=\(\dfrac{-5}{2}\)
2.
\(\left(\dfrac{1}{7.9}+\dfrac{1}{9.11}+...+\dfrac{1}{31.33}\right).x=\left(0,25-3,5\right).\dfrac{27}{3}\)
\(\dfrac{2}{2}.\left(\dfrac{1}{7.9}+\dfrac{1}{9.11}+...+\dfrac{1}{31.33}\right).x=-3,25.9\)
\(\dfrac{1}{2}.\left(\dfrac{2}{7.9}+\dfrac{2}{9.11}+...+\dfrac{2}{31.33}\right).x=-29,25\)
\(\dfrac{1}{2}.\left(\dfrac{1}{7}-\dfrac{1}{33}\right).x=-29,25\)
\(\dfrac{1}{2}.\dfrac{26}{231}.x=-29,25\)
\(\dfrac{13}{231}.x=-29,25\)
\(x=-29,25:\dfrac{13}{231}\)
\(x=\dfrac{-2079}{4}\)
tick mink nha :)
28 tháng 4 2016
Ta có: x + 30 % x = -131/100
x ( 1 + 30%) = -131/100
x 13/10=-131/100
x = -131/100 ; 13/10
x = -131/130
b) )x+3/-15=1/3
x = 1/3 -3/-15
x= 8/15
=> x = \(\frac{8}{15}\)
28 tháng 4 2016
Ta có: x + 30 % x = -131/100
x ( 1 + 30%) = -131/100
x 13/10=-131/100
x = -131/100 ; 13/10
x = -131/130
\(x+\dfrac{30}{100}.x=-1,31\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ x.\left(1+\dfrac{30}{100}\right)=\dfrac{-131}{100}\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ x.\left(\dfrac{100}{100}+\dfrac{30}{100}\right)=\dfrac{-131}{100}\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ x.\dfrac{26}{20}=\dfrac{-131}{100}\\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\\\ \\ x=\dfrac{-131}{100}:\dfrac{26}{20}=\dfrac{-131}{100}.\dfrac{20}{26}\\ \\ \\ \\ \\ \\ \\ \\ \\\\ \\ x=\dfrac{-131}{130}\)
coi chừng mình làm sai nhưng trinh bày mình đúng nhưng cẩn thận kết quả. nhé bye
x+\(\dfrac{30}{100}\).x=-1,31
x+0,3.x=-1,31
x.(0,3+1)=-1,31
x.1,3=-1,31
x=-1,31:1,3
x=\(\dfrac{-131}{130}\)
Vậy x=\(\dfrac{-131}{130}\)
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