9/14 - x/7 : 5/3 = 3/14 

9/14 - x x 1/7 x 3/5 = 3/14

x x 3/35 = 9/14 - 3/14

x x 3/35 = 3/7 

x = 3/7 : 3/35

 x = 5 

vậy x =5

a,x.(3\4+2\5)=1

x.20\23=1

x=1:20\23

x=20\23

b,x-9\11=0 hoặc x-25\31=0

x=9\11                x=25\31

c,x-3\7.9\14=7\3

x-2\3=7\3

x=7\3+2\3

x=9\3

x=3

a.\(\dfrac{9}{14}:x=\dfrac{3}{7}\)

\(x=\dfrac{9}{14}:\dfrac{3}{7}\)

\(x=\dfrac{3}{2}\)

b.\(\dfrac{7}{15}\times x=\dfrac{7}{10}\)

\(x=\dfrac{7}{10}:\dfrac{7}{15}\)

\(x=\dfrac{3}{2}\)

a: x=9/14:3/7=9/14x7/3=63/42=3/2

b: x=7/10:7/15=15/10=3/2

a,x=9/14:3/7

x=9/14.7/3

x=3/2

b,x=7/10:7/15

x=7/10.15/7

x=3/2

a.\(\left(-12\right)x-14=-2\)

\(\left(-12\right)x=-2+14\)

\(\left(-12\right)x=12\)

\(x=12:\left(-12\right)\)

\(x=-1\)

\(b,\left(-8\right)x=\left(-5\right)\left(-7\right)-3\)

\(\left(-8\right)x=35-3\)

\(\left(-8\right)x=32\)

\(x=32:\left(-8\right)\)

\(x=-4\)

\(c,\left(-9\right)x+3=\left(-2\right)\left(-7\right)+16\)

\(\left(-9\right)x+3=14+16\)

\(\left(-9\right)x+3=30\)

\(\left(-9\right)x=30-3\)

\(\left(-9\right)x=27\)

\(x=27:\left(-9\right)\)

\(x=-3\)

                   Đề Bài :\(\frac{9}{14}\)- \(\frac{x}{7}\): \(\frac{5}{3}\)= \(\frac{3}{14}\)

ta có : \(\frac{9}{14}\)- \(\frac{x}{7}\)= \(\frac{3}{14}\)x \(\frac{5}{3}\)= \(\frac{5}{14}\)

          \(\frac{x}{7}\)= \(\frac{9}{14}\)- \(\frac{5}{14}\)= \(\frac{4}{14}\)

         \(\frac{4}{14}\)= \(\frac{x}{7}\)=> \(\frac{4}{14}\)= \(\frac{2}{7}\)=> x = 2

b: \(\Leftrightarrow\left(x-\dfrac{1}{2}\right):\dfrac{1}{3}=9+\dfrac{5}{7}-\dfrac{5}{7}=9\)

=>x-1/2=27

hay x=55/2

c: =>1/2x-3/4=42/63=2/3

=>1/2x=17/12

hay x=17/6

a.1/4

b.-7/144

c.25/21

d.17/7

e.80/63

f.9/7

a)1/4

b)-7/144

c)-25/21

d)17/7

e)16/63

f)9/7

\(\dfrac{15-x}{14}=\dfrac{5}{7}\\ \left(15-x\right)\times7=5\times14\\ \left(15-x\right)\times7=70\\ 15-x=70:7\\ 15-x=10\\ x=15-10\\ x=5\)

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\(\dfrac{x}{9}=\dfrac{17}{3}\\ x\times3=17\times9\\ x\times3=153\\ x=153:3\\ x=51\)

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\(15-\dfrac{x}{2}=\dfrac{3}{7}\\ \dfrac{x}{2}=15-\dfrac{3}{7}\\ \dfrac{x}{2}=\dfrac{102}{7}\\ x\times7=102\times2\\ x\times7=204\\ x=204:7\\ x=\dfrac{204}{7}\)

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