Tìm x

35 - (2x - 1) + 4 = 28

35 - (2x - 1) = 28 - 4

35 - (2x - 1) = 24

2x - 1 = 35 - 24

2x - 1 = 11

2x = 11 + 1

2x = 12

x = 12 : 2

x = 6

Vậy x = 6.

\(35-\left(2x-1\right)+4=28\)

\(< =>35-2x+1+4=28\)

\(< =>40-2x=28< =>2x=40-28\)

\(< =>2x=12< =>x=\frac{12}{2}=6\)

5. have you ever seen a real robot?

6. nam often watches in the evening

1. Where are you going now?

 - I am going to the theatre.

2. He doesn't do morning exercises regularly.

3. Is he doing morning exercises now?

4. If it is nice tomorrow, We will go on a picnic.

5. Nam often watches TV  in the evening.

Tìm \(x\inℚ\) đúng không bạn? ._.

a, \(A=\frac{7}{3x+1}=7\)

\(\Rightarrow3x+1=7\div7\)

\(3x+1=1\)

\(3x=0\)

\(x=0\)

Vậy x = 0.

b, \(A=\frac{7}{3x+1}=-5\)

\(\Rightarrow3x+1=7\div\left(-5\right)\)

3x + 1 = -1,4

3x = -1,4 - 1

3x = -2,4

x = -2,4 : 3

x = -8.

Vậy x = -8.

c, Để A là số hữu tỉ dương thì \(\frac{7}{3x+1}\) là số hữu tỉ dương

\(\Rightarrow\)3x + 1 > 0

\(\Rightarrow\)3x > -1

\(\Rightarrow x>-\frac{1}{3}\)

Vậy \(x>-\frac{1}{3}\)

d, A là số hữu tỉ âm thì \(\frac{7}{3x+1}\)là số hữu tỉ âm

\(\Rightarrow3x+1< 0\)

\(\Rightarrow3x< -1\)

\(\Rightarrow x< -\frac{1}{3}\)

Vậy \(x< -\frac{1}{3}\)

a) \(A=7\)\(\Leftrightarrow\frac{7}{3x+1}=7\)\(\Leftrightarrow3x+1=1\)\(\Leftrightarrow3x=0\)\(\Leftrightarrow x=0\)

Vậy \(x=0\)

b) \(A=-5\)\(\Leftrightarrow\frac{7}{3x+1}=-5\)\(\Leftrightarrow3x+1=\frac{-7}{5}\)\(\Leftrightarrow3x=\frac{-12}{5}\)\(\Leftrightarrow x=\frac{-4}{5}\)

Vậy \(x=\frac{-4}{5}\)

c) Vì \(7>0\)\(\Rightarrow\) Để A là số hữu tỉ dương thì \(3x+1>0\)\(\Leftrightarrow3x>-1\)\(\Leftrightarrow x>-\frac{1}{3}\)

Vậy \(x>\frac{-1}{3}\)

d) Vì \(7>0\)\(\Rightarrow\) Để A là số hữu tỉ âm thì \(3x+1< 0\)\(\Leftrightarrow3x< -1\)\(\Leftrightarrow x< \frac{-1}{3}\)

Vậy \(x< \frac{-1}{3}\)

\(x-\frac{1}{4}.x=\frac{5}{6}\)

\(x.\left(1-\frac{1}{4}\right)=\frac{5}{6}\)

\(x\left(\frac{4}{4}-\frac{1}{4}\right)=\frac{5}{6}\)

\(x.\frac{3}{4}=\frac{5}{6}\)

\(x=\frac{5}{6}:\frac{3}{4}\)

\(x=\frac{10}{9}\)

Học tốt

Trả lời:

\(x-\frac{1}{4}.x=\frac{5}{6}\)

\(\Leftrightarrow x.\left(1-\frac{1}{4}\right)=\frac{5}{6}\)

\(\Leftrightarrow x.\frac{3}{4}=\frac{5}{6}\)

\(\Leftrightarrow x=\frac{10}{9}\)

Vậy \(x=\frac{10}{9}\)

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><

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a,\(\left(x-2\right)\left(x+2\right)=0\)

\(< =>\orbr{\begin{cases}x-2=0\\x+2=0\end{cases}< =>\orbr{\begin{cases}x=2\\x=-2\end{cases}}}\)

b,\(\left(\frac{3}{4}x-\frac{1}{2}\right)\left(0,25x+\frac{4}{3}\right)=0\)

\(< =>\orbr{\begin{cases}\frac{3x}{4}-\frac{2}{4}=0\\\frac{3x}{12}+\frac{16}{12}=0\end{cases}}\)

\(< =>\orbr{\begin{cases}3x-2=0\\3x+16=0\end{cases}}< =>\orbr{\begin{cases}x=\frac{2}{3}\\x=-\frac{16}{3}\end{cases}}\)

\(\left(x-2\right)\left(x+2\right)=0\)

=> \(\orbr{\begin{cases}x-2=0\\x+2=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)

\(\left(\frac{3}{4}x-\frac{1}{2}\right)\left(0,25x+\frac{4}{3}\right)=0\)

=> \(\orbr{\begin{cases}\frac{3}{4}x-\frac{1}{2}=0\\0,25x+\frac{4}{3}=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{2}{3}\\x=-\frac{16}{3}\end{cases}}\)

a. bau troi rong lon;b.hom nay toi rat den dui;mua dong rat lanh leo

1. khu vườn này thật rộng lớn / phòng của huy thật rộng rãi

2. nước da đen đúa / hôm nay huy thật đen đủi

3. ngôi nhà này thật lạnh lẽo / cậu ấy thật lạnh lùng

4. nơi đây thật thanh bình / ông ấy chết một cách thanh thản 

\(A=\left\{x\in N|x< 50\right\}\)

mình có thể làm sai xin lỗi

\(\frac{x}{7}=\frac{x+16}{35}\)

\(\Leftrightarrow x\cdot35=7\left(x+16\right)\)

\(\Leftrightarrow35x=7x+112\)

\(\Leftrightarrow35x-7x=112\)

\(\Leftrightarrow28x=112\)

\(\Leftrightarrow x=4\)

Vậy x = 4

\(\frac{8}{x}=\frac{7}{x-16}\)

\(\Leftrightarrow8\left(x-16\right)=x\cdot7\)

\(\Leftrightarrow8x-128=7x\)

\(\Leftrightarrow8x-7x=128\)

\(\Leftrightarrow x=128\)

Vậy x = 128

a,\(\frac{x}{7}=\frac{x+16}{35}< =>\frac{5x}{35}=\frac{x+16}{35}\)

\(< =>5x=x+16\)

\(< =>4x=16< =>x=4\)

b,\(\frac{8}{x}=\frac{7}{x-16}\)\(< =>8x-128=7x\)

\(< =>x=128\)

Tìm x

\(\frac{1}{3}+\frac{2}{2\left(x+1\right)}=1\)

\(\frac{1}{3}+\frac{1}{x+1}=1\)

\(\frac{1}{x+1}=1-\frac{1}{3}\)

\(\frac{1}{x+1}=\frac{3}{3}-\frac{1}{3}\)

\(\frac{1}{x+1}=\frac{2}{3}\)

\(\Rightarrow2\left(x+1\right)=3\)

\(\Rightarrow x+1=\frac{3}{2}\)

\(\Rightarrow x=\frac{1}{2}\)

Bài làm:

đkxđ: \(x\ne-1\)

Ta có: \(\frac{1}{3}+\frac{2}{2\left(x+1\right)}=1\)

\(\Leftrightarrow\frac{1}{3}+\frac{1}{x+1}=1\)

\(\Leftrightarrow\frac{x+1+3}{3\left(x+1\right)}=1\)

\(\Leftrightarrow x+4=3x+3\)

\(\Leftrightarrow2x=1\)

\(\Rightarrow x=\frac{1}{2}\)