a) (3/4 + x ) × 7/4 - 5 = 7/6
b) X × 12 + 13 × x + x ÷ 2 + 195 =1995
c) (x + 1 ) + (x + 4 ) + (x + 7) + ...... + ( x + 28 ) = 156
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11 tháng 3 2022
a: =>x=-7/6+5/8=-13/24
b: =>x=-14/25-3/4=-131/100
c: \(x=\dfrac{-33}{26}:\dfrac{-9}{13}=\dfrac{33}{26}\cdot\dfrac{13}{9}=\dfrac{11}{3}\cdot\dfrac{1}{2}=\dfrac{11}{6}\)
d: \(x=\dfrac{4}{9}:\dfrac{5}{3}=\dfrac{4}{9}\cdot\dfrac{3}{5}=\dfrac{12}{45}=\dfrac{4}{15}\)
10 tháng 5 2023
2: \(=\dfrac{-2}{75}+\dfrac{5}{39}=\dfrac{33}{325}\)
3: \(=\dfrac{6}{11}\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{6}{11}\)
4: \(=\dfrac{7}{19}\left(\dfrac{5}{13}+\dfrac{8}{13}-1\right)=-2\cdot\dfrac{7}{19}=-\dfrac{14}{19}\)
5: \(=\dfrac{2}{7}\left(\dfrac{4}{23}-\dfrac{27}{23}+1\right)=0\)
6: \(=\dfrac{3}{8}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\dfrac{11}{8}=\dfrac{3}{8}+\dfrac{11}{8}=\dfrac{14}{8}=\dfrac{7}{4}\)
7 tháng 8 2019
\(1,\frac{2}{3}+\frac{4}{9}+\frac{1}{5}+\frac{2}{15}+\frac{3}{2}-\frac{17}{18}\)
\(< =>\frac{4}{9}+\frac{3}{2}+\left(\frac{2}{3}+\frac{1}{5}+\frac{2}{15}\right)-\frac{17}{18}\)
\(< =>\frac{8}{18}+\frac{27}{18}+\left(\frac{10}{15}+\frac{3}{15}+\frac{2}{15}\right)-\frac{17}{18}\)
\(< =>\frac{35}{18}+1-\frac{17}{18}\)
\(< =>\frac{53}{18}-\frac{17}{18}\)
\(< =>2\)
\(2,\frac{13}{28}\cdot\frac{5}{12}-\frac{5}{28}\cdot\frac{1}{12}\)
\(< =>\left(\frac{13}{28}-\frac{5}{28}\right)\cdot\left(\frac{5}{12}-\frac{1}{12}\right)\)
\(< =>\frac{2}{7}\cdot\frac{1}{3}\)
\(< =>\frac{2}{21}\)
\(3,\frac{19}{4}\cdot\frac{15}{23}-\frac{15}{4}\cdot\frac{7}{23}+\frac{15}{4}\cdot\frac{11}{23}\)
\(< =>\frac{285}{92}-\frac{105}{92}+\frac{165}{92}\)
\(< =>\frac{15}{4}\)
LH
2
LM
1 tháng 4 2020
a)7-3x=28
3x =7-28
3x =-21
x =-21:3
x =-7
b)12-x=13-(-4)
12-x=13+4
12-x=17
x=12-17
x=-5
c)15-2(x-1)=-3
2(x-1) =15+3
2(x-1) =18
x-1 =18:2
x =9+1
x =10
d)2x-(3+x)=5-7
2x-(3+x)=-2
3+x =2x+2
3+x-2 =2x
x+1 =2x
x+1 =x+x
=>x=1
#Chúc bạn học tốt#
k cho mk nha ,please!!!
1 tháng 4 2020
a) 7 - 3x = 28
3x = 7 - 28
3x = -21
x = -21 : 3
x = -7
vậy x = -7
b) 12 - x = 13 -(-4)
12 - x = 17
x = 12 - 17
x = -5
vậy x = -5
c) 15 - 2 . (x - 1) = -3
2 . (x - 1) = 15 -(-3)
2 . (x - 1) = 18
x - 1 = 18 : 2
x - 1 = 9
x = 9 + 1
x = 10
vậy x = 10
d) 2x - (3 + x) = 5 - 7
2x - (3 + x) = -2
3 + x = 2x -(-2)
3 + x - 2 = 2x
x + 1 = 2x
x + 1 = x + x
=> x = 1
vậy x = 1
k cho mk nha
a) \(\left(\frac{3}{4}+x\right)\times\frac{7}{4}-5=\frac{7}{6}\)
\(\Leftrightarrow\left(\frac{3}{4}+x\right)\times\frac{7}{4}=\frac{37}{6}\)
\(\Leftrightarrow\frac{3}{4}+x=\frac{37}{6}:\frac{7}{4}=\frac{74}{21}\)
\(\Leftrightarrow x=\frac{74}{21}-\frac{3}{4}=\frac{233}{84}\)
Vậy ....
b) \(x\times12+13\times x+x:2+195=1995\)
\(\Leftrightarrow x\times12+x\times13+x\times0,5=1800\)
\(\Leftrightarrow x\times\left(12+13+0,5\right)=1800\)
\(\Leftrightarrow x\times25,5=1800\)
\(\Leftrightarrow x=\frac{1200}{17}\)
c) (x+1)+(x+4)+(x+7)+....+(x+28) = 156
<=> (x+x+x+...+x)+(1+4+7+...+28) = 156
<=> 10x + 145 = 156
<=> 10x = 11
<=> x = 1,1
Vậy ...