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Ta có: \(\left(\dfrac{3}{5}+0.415-\dfrac{3}{200}\right)\cdot2\dfrac{2}{3}\cdot0.25\)

\(=\left(\dfrac{120}{200}+\dfrac{83}{200}-\dfrac{3}{200}\right)\cdot\dfrac{8}{3}\cdot\dfrac{1}{4}\)

\(=\dfrac{8}{3}\cdot\dfrac{1}{4}=\dfrac{8}{12}=\dfrac{2}{3}\)

a: \(\Leftrightarrow2x+\dfrac{7}{2}=\dfrac{16}{3}:\dfrac{11}{3}=\dfrac{16}{11}\)

=>2x=-45/22

hay x=-45/44

b: =>x/7=-1/28:1/4=-1/7

=>x=-1

10 tháng 3 2022

a)(7/2+2x).11/3=16/3

7/2+2x=16/3:11/3

7/2+2x=16/3.3/11

7/2+2x=16/11

2x=16/11-7/2

2x= -45/22

x= -45/22:2

x= -45/44

Vậy x= -45/44

b)x/7 +1/4= -1/28

x/7= -1/28-1/4

x/7= -2/7

=>x= -2

11 tháng 7 2017

d, 32%-0,25:x=-3/2/5

0,32-0,25:x=-3,4

-0,25:x=-3,4-0,32

-0,25:x=-3,72

x=-0,25:-3,72

x=25/372

11 tháng 7 2017

7/8+4/1/2:x=-13/40

0,875+4,5:x=-0,325

4,5:x=-0,325-0,875

4,5:x=-1,2

x=4,5:-1,2

x=-3,75

23 tháng 4 2017

9) \(\dfrac{x}{4}=\dfrac{9}{x}\)

Theo định nghĩa về hai phân số bằng nhau, ta có:

\(4\cdot9=x^2\\ 36=x^2\Rightarrow\left[{}\begin{matrix}x=6\\x=-6\end{matrix}\right.\)

8)

\(x:\dfrac{5}{3}+\dfrac{1}{3}=-\dfrac{2}{5}\\ x:\dfrac{5}{3}=-\dfrac{2}{5}+\dfrac{1}{3}\\ x:\dfrac{5}{3}=-\dfrac{1}{15}\\ x=\dfrac{1}{15}\cdot\dfrac{5}{3}\\ x=\dfrac{1}{9}\)

7)

\(2x-16=40+x\\ 2x-x=40+16\\ x\left(2-1\right)=56\\ x=56\)

6)

\(1\dfrac{1}{2}+x=\dfrac{3}{2}-7\\ \dfrac{3}{2}+x=\dfrac{3}{2}-7\\ \dfrac{3}{2}-\dfrac{3}{2}=-7-x\\ -7-x=0\\ x=-7-0\\ x=-7\)

5)

\(3\dfrac{1}{2}-\dfrac{1}{2}x=\dfrac{2}{3}\\ \dfrac{7}{2}-\dfrac{1}{2}x=\dfrac{2}{3}\\ \dfrac{1}{2}x=\dfrac{7}{2}-\dfrac{2}{3}\\ \dfrac{1}{2}x=\dfrac{17}{6}\\ x=\dfrac{17}{6}:\dfrac{1}{2}\\ x=\dfrac{17}{3}\)

4)

\(x\cdot\left(x+1\right)=0\Rightarrow\left[{}\begin{matrix}x=0\\x+1=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=0\\x=-1\end{matrix}\right.\)

3)

\(\left(\dfrac{2x}{5}+2\right):\left(-4\right)=-1\dfrac{1}{2}\\ \left(\dfrac{2x}{5}+2\right):\left(-4\right)=-\dfrac{3}{2}\\ \dfrac{2x}{5}+2=-\dfrac{3}{2}\cdot\left(-4\right)\\ \dfrac{2x}{5}+2=6\\ \dfrac{2x}{5}=6-2\\ \dfrac{2x}{5}=4\\ 2x=4\cdot5\\ 2x=20\\ x=20:2\\ x=10\)

2)

\(\dfrac{1}{3}+\dfrac{1}{2}:x=-0,25\\ \dfrac{1}{3}+\dfrac{1}{2}:x=-\dfrac{1}{4}\\ \dfrac{1}{2}:x=-\dfrac{1}{4}-\dfrac{1}{3}\\ \dfrac{1}{2}:x=-\dfrac{7}{12}\\ x=\dfrac{1}{2}:-\dfrac{7}{12}\\ x=-\dfrac{6}{7}\)

1)

\(\dfrac{4}{3}+x=\dfrac{2}{15}\\ x=\dfrac{2}{15}-\dfrac{4}{3}x=-\dfrac{6}{5}\)

a: =>4x-5=0 hoặc 5/4x-2=0

=>x=5/4 hoặc x=2:5/4=2*4/5=8/5

b: =>(1/12+19/6-30,75)*x-8=102

=>-55/2x=110

=>x=-4

2 tháng 5 2017

6. \(\dfrac{x}{4}=\dfrac{9}{x}\)

=>x2=4.9=36

=>x\(\in\)\(\left\{-6;6\right\}\)

27 tháng 8 2023

\((\dfrac{2x}{5}+2):\left(-4\right)=-1\dfrac{1}{2}\) 

(\(\dfrac{2x}{5}+2):\left(-4\right)=-\dfrac{3}{2}\) 

\(\dfrac{2x}{5}=-\dfrac{3}{2}.\left(-4\right)\) 

\(\dfrac{2x}{5}=6\) 

\(\dfrac{2x}{5}=\dfrac{30}{5}\) 

2x = 30 

x = 30 : 2 = 15

30 tháng 4 2017

a,(3/5+0,415-3/200).\(2\dfrac{2}{3}\).0,25

=(0,6+0.415-3/200)8/3.1/4

=(1,015-3/200).8/3.1/4

=(1015/1000-3/200).2/3

=(203/200-3/200).2/3

=1.2/3=2/3

b,0,25:(10,3-9,8)-3/4

=0,25:910,3-9,8)-0.75

=0,25:0,5-0,75

=-0,25

Mình làm từng đó trước,lần sau mình sẽ lm típ nha!hiha

1 tháng 5 2017

Mình tick đúng nhưng bạn cần đọc rõ đề Tính theo cách hợp lý nhất

1 tháng 10 2023

a) \(0,25-\dfrac{2}{3}+1\dfrac{1}{4}\)

\(=\dfrac{1}{4}-\dfrac{2}{3}+\dfrac{5}{4}\)

\(=\dfrac{3}{12}-\dfrac{8}{12}+\dfrac{15}{12}\)

\(=\dfrac{10}{12}\)

\(=\dfrac{5}{6}\)

\(---\)

b) \(\dfrac{3^2}{2}:\dfrac{1}{4}+\dfrac{3}{4}\cdot2010\)

\(=\dfrac{9}{2}\cdot4+\dfrac{3015}{2}\)

\(=18+\dfrac{3015}{2}\)

\(=\dfrac{36}{2}+\dfrac{3015}{2}\)

\(=\dfrac{3051}{2}\)

\(---\)

c) \(\left\{\left[\left(\dfrac{1}{25}-0,6\right)^2:\dfrac{49}{125}\right]\cdot\dfrac{5}{6}\right\}-\left[\left(\dfrac{-1}{3}\right)+\dfrac{1}{2}\right]\)

\(=\left\{\left[\left(-\dfrac{14}{25}\right)^2:\dfrac{49}{125}\right]\cdot\dfrac{5}{6}\right\}-\left[\left(\dfrac{-2}{6}\right)+\dfrac{3}{6}\right]\)

\(=\left\{\left[\dfrac{196}{625}\cdot\dfrac{125}{49}\right]\cdot\dfrac{5}{6}\right\}-\dfrac{1}{6}\)

\(=\left\{\dfrac{4}{5}\cdot\dfrac{5}{6}\right\}-\dfrac{1}{6}\)

\(=\dfrac{4}{6}-\dfrac{1}{6}\)

\(=\dfrac{3}{6}\)

\(=\dfrac{1}{2}\)

\(---\)

d) \(\left(-\dfrac{1}{2}-\dfrac{1}{3}\right)^2:\left[\left(\dfrac{-5}{36}\right)-\left(\dfrac{-5}{36}\right)^0\right]\)

\(=\left(-\dfrac{3}{6}-\dfrac{2}{6}\right)^2:\left[-\dfrac{5}{36}-1\right]\)

\(=\left(-\dfrac{5}{6}\right)^2:\left[-\dfrac{5}{36}-\dfrac{36}{36}\right]\)

\(=\dfrac{25}{36}:\left(\dfrac{-41}{36}\right)\)

\(=\dfrac{25}{36}\cdot\left(\dfrac{-36}{41}\right)\)

\(=-\dfrac{25}{41}\)

#\(Toru\)

1 tháng 10 2023

cảm ơn nhiều nha vừa kịp giờ lun

12 tháng 3 2022

a)4/5+x=2/3

x=2/3-4/5

x=-2/15

b)-5/6-x=2/3

x=-5/6-2/3

x=-3/2

c)1/2x+3/4=-3/10

1/2x=-3/10-3/4

1/2x=-21/20

x=-21/20:1/2

x=-21/10

d)x/3-1/2=1/5

x/3=1/5+1/2

x/3=7/10

10x/30=21/30

10x=21

x=21:10

x=21/10