\(5\cdot7\cdot12=420\)

\(6\cdot9\cdot15=810\)

\(5\cdot9\cdot14=630\)

\(7\cdot11\cdot18=1386\)

5*7*12=420

6*9*15=810

5**9*14=630

7*11*18=1386

5 x 7 x 12 = 420

6 x 9 x 15 = 810

5 x 9 x 14 = 630

7 x 11 x 18 = 1386

Thấy Được Thì Tk Cho Mình Nhé!

a: x-4/5=3/7

=>x=3/7+4/5=43/35

b: x+3/7=4/5

=>x=4/5-3/7=13/35

c: 19/20-x=8/5-3/4

=>19/20-x=32/20-15/20=17/20

=>x=2/20=1/10

d: =>4/5*x=2/21

=>x=2/21:4/5=5/42

e: =>x:7/9=6/8

=>x=6/8*7/9=3/4*7/9=21/36=7/12

f: =>x/6=2/3-1/3=1/3

=>x=2

a: x-4/5=3/7

=>x=3/7+4/5=43/35

b: x+3/7=4/5

=>x=4/5-3/7=13/35

c: 19/20-x=8/5-3/4

=>19/20-x=32/20-15/20=17/20

=>x=2/20=1/10

d: =>4/5*x=11/21

=>x=55/84

e: =>x=6/8*7/9=42/72=7/12

f: =>x/6=2/3-1/3=1/3

=>x=2

a) \(55-4x-4\left(-x+3\right)=6-2\left(-8-3x\right)\)

\(55-4x+4x-12=6+16+6x\)

\(43-6-16=6x\)

\(6x=21\)

\(x=3,5\)

b) \(-5\left(-2x-6\right)-9\left(4-7x\right)=51-3x+6\left(x-9\right)\)

\(10x+30-36+63x=51-3x+6x-54\)

\(73x-6=-3+3x\)

\(73x-3x=-3+6\)

\(70x=3\)

\(x=\frac{3}{70}\)

c) \(93+\left|6-3x\right|-39=231\)

\(\left|6-3x\right|+54=231\)

\(\left|6-3x\right|=177\)

\(\Rightarrow\orbr{\begin{cases}6-3x=177\\6-3x=-177\end{cases}}\Rightarrow\orbr{\begin{cases}3x=6-177\\3x=6+177\end{cases}}\Rightarrow\orbr{\begin{cases}3x=-171\\3x=183\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-57\\x=61\end{cases}}\)

a)       \(55-4x-4\left(-x+3\right)=6-2\left(-8-3x\right)\)

\(\Leftrightarrow\)\(55-4x+4x-12=6+16+6x\)

\(\Leftrightarrow\)\(6x+22=43\)

\(\Leftrightarrow\)\(6x=43-22=21\)

\(\Leftrightarrow\)\(x=21:6=3.5\)

Vậy...

b)pt\(\Leftrightarrow10x+30-36+63x=51-3x+6x-54\)

tự tiếp

\(\left(\frac{5}{7}-x\right)\cdot\frac{14}{5}=\frac{7}{10}+\frac{1}{2}\)

\(\left(\frac{5}{7}-x\right)\cdot\frac{14}{5}=\frac{6}{5}\)

\(\left(\frac{5}{7}-x\right)=\frac{6}{5}\div\frac{14}{5}\)

\(\frac{5}{7}-x=\frac{3}{7}\)

            \(x=\frac{5}{7}-\frac{3}{7}\)

             \(x=\frac{2}{7}\)

\(\left(\frac{5}{7}-x\right).\frac{14}{5}=\frac{7}{10}+\frac{1}{2}\)

<=> \(\left(\frac{5}{7}-x\right).\frac{14}{5}=\frac{6}{5}\)

<=> \(\frac{5}{7}-x=\frac{3}{7}\)

<=> \(x=\frac{2}{7}\)

\(a,\dfrac{5}{8}=\dfrac{x}{14}\)

\(\Rightarrow x=\dfrac{5.14}{8}=8,75\)

Vậy \(x=8,75\)

\(b,\dfrac{x}{6}=-\dfrac{1}{3}\)

\(\Rightarrow x=-\dfrac{1.6}{3}=-2\)

Vậy \(x=-2\)

\(c,-\dfrac{3}{5}=\dfrac{x}{10}\)

\(\Rightarrow x=-\dfrac{3.10}{5}=-6\)

Vậy \(x=-6\)

câu d đã có đáp án

mik đang cần gấp ak

\(+\text{)}\dfrac{5}{8}=14x\)⇒\(x=\dfrac{5}{112}\)

\(+\text{)}\dfrac{x}{6}=-\dfrac{1}{3}\)⇒\(x=-2\)

\(+\text{)}-\dfrac{3}{5}=\dfrac{x}{10}\)⇒\(x=-6\)

\(+\text{)}\dfrac{3}{5}=-\dfrac{9}{11}\)⇒\(\dfrac{33}{55}=\dfrac{45}{55}\)

\(+\text{)}\dfrac{x}{2}=\dfrac{2}{x}\)⇒\(x=+-2\)

\(+\text{)}\dfrac{x}{-5}=\dfrac{-5}{x}\)⇒\(x=+-5\)

a)7x+2x=918;           

9x=918

x=102.

Vay x=102.

x - 4/5 = 3/7

x = 3/7 + 4/5

x = 43/35

x + 3/7 = 4/5

x = 4/5 - 3/7

x = 13/35

19/20 - x = 8/5 - 3/4

19/20 - x =  17/20

x = 19/20 - 17/20

x = 2/20 = 1/10

4/5 x X = 6/9 - 4/7

4/5 x X = 2/21

x = 2/21 : 4/5

x =5/42

x : 7/9 = 6/8

x = 6/8 x 7/9

x = 7/12

2/3 - x/6 = 6/18

x/6 = 2/3 - 6/18

x/6 = 1/3

x/6 = 2/6

=> x =2

1. x = 43/35

2. x = 13/35

3. x = 1/10

còn lại tự tính nhá

tui bận òi

\(\left(\frac{5}{7}:y\right)\cdot\frac{14}{5}=\frac{7}{10}+\frac{1}{2}\)

\(\frac{5}{7}:y\cdot\frac{14}{5}=\frac{7}{10}+\frac{5}{10}\)

\(\frac{5}{7}\cdot\frac{14}{5}:y=\frac{12}{10}\)

\(2:y=\frac{12}{10}\)

\(y=2:\frac{12}{10}\)

\(y=2\cdot\frac{10}{12}\)

\(y=\frac{5}{3}\)

Câu này trong Violympic chứ gì !? Mình đọc lại đề bài thì thấy sai, mình sửa lại thành: Tìm y biết \(\left(\frac{5}{7}-y\right)\times\frac{14}{5}=\frac{7}{10}+\frac{1}{2}\)

\(\left(\frac{5}{7}-y\right)\times\frac{14}{5}=\frac{7}{10}+\frac{5}{10}\)

\(\left(\frac{5}{7}-y\right)\times\frac{14}{5}=\frac{12}{10}\)

\(\frac{5}{7}-y=\frac{12}{10}:\frac{14}{5}\)

\(\frac{5}{7}-y=\frac{3}{7}\)

\(y=\frac{5}{7}-\frac{3}{7}\)

\(y=\frac{2}{7}\)

Bạn Mai Thanh Xuân sai rồi nha

(5/7:y)*14/5=7/10+1/2

(5/7:y)*14/5=6/5

5/7:y=6/5:14/5

5/7:y=3/7

y=5/7:3/7

y=5/3

Vậy y=5/3