Tìm y
y+30%.y= -1,3 y-25%.y= 1/2
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MT
0
LT
2
NK
3
PN
30 tháng 3 2016
a,y+30%y=-1,3
y+3/10y=-1,3
y(1+3/10)=-1,3
y(10/10+3/10)=-1,3
13/10y=-13/10
y=-13/10:13/10
y=-1
Vậy y=-1
b,y-25%y=1/2
y-1/4y=1/2
y(1-1/4)=1/2
y(4/4-1/4)=1/2
3/4y=1/2
y=1/2:3/4
y=3/8
Vậy y=3/8
30 tháng 3 2016
a/ y + 30%y = -1,3
=> y + \(\frac{3}{10}\)y = -1,3
=> \(\frac{13}{10}\)y = -1,3
=> y = -1
b/ y - 25%.y = \(\frac{1}{2}\)
=> y - \(\frac{1}{4}\)y = \(\frac{1}{2}\)
=> \(\frac{3}{4}\)y = \(\frac{1}{2}\) => y = \(\frac{2}{3}\)
LM
0
LH
4 tháng 4 2017
\(a)\) \(y+30\%=\dfrac{-1}{3}\)
\(\Rightarrow y+\dfrac{3}{10}=\dfrac{-1}{3}\)
\(\Rightarrow y=\dfrac{-19}{30}\)
Vậy ...
\(b)\) \(y-25\%y=\dfrac{1}{2}\)
\(\Rightarrow1y-\dfrac{1}{4}y=\dfrac{1}{2}\)
\(\Rightarrow y\left(1-\dfrac{1}{4}\right)=\dfrac{1}{2}\)
\(\Rightarrow y\dfrac{3}{4}=\dfrac{1}{2}\)
\(\Rightarrow y=\dfrac{2}{3}\)
Vậy .....
S
4 tháng 4 2017
a, \(y+30\%=-1,3\)
\(\Rightarrow y=-\dfrac{13}{10}-\dfrac{3}{10}\)
\(\Rightarrow y=\dfrac{-8}{10}\)
b, \(y-25\%y=\dfrac{1}{2}\)
\(\Rightarrow y\left(1-\dfrac{1}{4}\right)=\dfrac{1}{2}\)
\(\Rightarrow\dfrac{3}{4}y=\dfrac{1}{2}\)
\(\Rightarrow y=\dfrac{1}{2}:\dfrac{3}{4}\)
\(\Rightarrow y=\dfrac{2}{3}\)
Q
11 tháng 4 2017
a)
\(y+30\%y=-1,3\\ \Leftrightarrow y+\dfrac{3}{10}y=-\dfrac{13}{10}\\ \Leftrightarrow y\left(1+\dfrac{3}{10}\right)=-\dfrac{13}{10}\\ \Leftrightarrow\dfrac{13}{10}y=-\dfrac{13}{10}\\ \Rightarrow y=-\dfrac{13}{10}:\dfrac{13}{10}\\ \Rightarrow y=-1\)
b)
\(y-25\%y=\dfrac{1}{2}\\ \Leftrightarrow y-\dfrac{1}{4}y=\dfrac{1}{2}\\\Leftrightarrow y\left(1-\dfrac{1}{4}\right)=\dfrac{1}{2} \\ \Leftrightarrow\dfrac{3}{4}y=\dfrac{1}{2}\\ \Rightarrow y=\dfrac{1}{2}:\dfrac{3}{4}\\ \Rightarrow y=\dfrac{1}{2}\cdot\dfrac{4}{3}\\ \Rightarrow y=\dfrac{4}{6}\\ \Rightarrow y=\dfrac{2}{3}\)
LH
1
4 tháng 4 2018
a, y + 30%y = -1,3
1.y + 30/100y = -13/10
1.y + 3/10y = -13/10
(1 + 3/10). y = -13/10
13/10 .y = -13/10
y = -13/10 : 13/10
y = -13/10 . 10/13
y = -1
b, y - 25%y = 1/2
1.y - 25/100.y = 1/2
1.y - 1/4.y = 1/2
(1 - 1/4) y = 1/2
3/4 .y = 1/2
y = 1/2 : 3/4
y = 1/2 . 4/3
y = 2/3
câu c mik chưa nghĩ ra
LT
0
SD
5
LM
15 tháng 8 2016
a)\(y+30\%y=-1,3\Rightarrow y+\frac{3}{10}y=-1,3\Rightarrow y\left(1+\frac{3}{10}\right)=-1,3\Rightarrow y\times1,3\)\(=-1,3\Rightarrow y=-1\)
b)\(y-25\%y=\frac{1}{2}\Rightarrow y-\frac{1}{4}y=\frac{1}{2}\Rightarrow y\left(1-\frac{1}{4}\right)=\frac{1}{2}\Rightarrow y\times\frac{3}{4}=\frac{1}{2}\Rightarrow y=\frac{1}{2}:\frac{3}{4}\Rightarrow y=\frac{2}{3}\)
c)\(3\frac{1}{3}y+16\frac{3}{4}=13,25\Rightarrow\frac{10}{3}y+\frac{67}{4}=\frac{53}{4}\Rightarrow\frac{10}{3}y=\frac{53}{4}-\frac{67}{4}\Rightarrow\frac{10}{3}y=\frac{-7}{2}\Rightarrow y=\frac{-21}{20}\)
Ban Phạm Thị Le linh oi bancos thể giúp minh giải ra ro ràng dc ko? please
y+30%.y=-1,3=y.130%=-1,3 y-25%.y=1/2=y.75%
y=-1,3:130% y=1/2:75%=2/3
y=-1