Tìm y, biết:
a. y + 30%y = -1,3
b. y - 25%y = 1/2
c. 3/1/3y + 16/3/4 = -13,25
Các bạn cố gắng giúp mik nha!
(Còn kí hiệu 3/1/3 có nghĩa là 3 và 1 phần 3, còn mấy câu khác thì tự hiểu)
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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
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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)\(3\frac{1}{3}y+16\frac{3}{4}=13,25\Rightarrow\frac{10}{3}y+\frac{67}{4}=\frac{53}{4}\Rightarrow\frac{10}{3}y=\frac{53}{4}-\frac{67}{4}\Rightarrow\frac{10}{3}y=\frac{-7}{2}\Rightarrow y=\frac{-21}{20}\)
a: =>y+3/10y=-1,3
=>13/10y=-1,3
hay y=-1
b: =>3/4y=1/2
hay y=2/3
c: \(\Leftrightarrow y\cdot\dfrac{19}{3}+16,75=-13,25\)
\(\Leftrightarrow y\cdot\dfrac{19}{3}=-30\)
hay y=-190