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a; 3:\(\frac{2x}{5}\)= 1:0.001
3:\(\frac{2x}{5}\)=1000
\(\frac{2x}{5}\)=1000:3
\(\frac{2x}{5}\)=0.003
2x=0.003.5
2x=0.015
x=0.015:2
x=7.5
b)
\(4\frac{5}{9}:2\frac{5}{18}-7< x< \left(3\frac{1}{5}:3,2+4,5.1\frac{31}{45}\right):\left(21.\frac{1}{2}\right)\)
\(\Rightarrow\frac{41}{9}:\frac{41}{18}-7< x< \left(\frac{16}{5}:\frac{16}{5}+\frac{9}{2}.\frac{76}{45}\right):\frac{21}{2}\)
\(\Rightarrow2-7< x< \left(1+\frac{38}{5}\right):\frac{21}{2}\)
\(\Rightarrow-5< x< \frac{43}{5}:\frac{21}{2}\)
\(\Rightarrow-5< x< \frac{86}{105}\)
Vì \(x\in Z\left(gt\right)\)
\(\Rightarrow x\in\left\{-4;-3;-2;-1;0\right\}.\)
Vậy \(x\in\left\{-4;-3;-2;-1;0\right\}.\)
10 - { [ ( x : 3 + 17 ) : 10 + 3 : 24 ] : 10 } = 5
[ ( x : 3 + 17 ) : 10 + 3 : 24 ] : 10 = 10 - 5 = 5
( x : 3 + 17 ) : 10 + 3 : 24 = 5 x 10
( x : 3 + 17 ) : 10 + 48 = 50
( x : 3 + 17 ) : 10 = 50 - 48
( x : 3 + 17 ) : 10 = 2
x : 3 + 17 = 2 x 10
x : 3 + 17 = 20
x : 3 = 20 - 17 = 3
x = 3 x 3 = 9
a) [(2x+14) : 4 - 3] : 2 = 1
(2x+14) : 4 - 3 = 1/2
(2x+14) : 4 = 1/2 + 3
(2x+14) : 4 = 7/2
2x+14 = 7/2 . 1/4
2x = 7/8 - 1/4
2x = 5/8
x= 5/8.1/2
x= 5/16
\(.2.\)
\(a.\)
\(2x+\dfrac{1}{2}=-\dfrac{5}{3}\)
\(\Rightarrow2x=-\dfrac{5}{3}-\dfrac{1}{2}=-\dfrac{13}{6}\)
\(\Rightarrow x=-\dfrac{13}{6}:2=-\dfrac{13}{12}\)
Vậy : \(x=-\dfrac{13}{12}\)
\(b.\)
\(\dfrac{1}{7}-\dfrac{3}{5}x=\dfrac{3}{5}\)
\(\Rightarrow\dfrac{3}{5}x=\dfrac{1}{7}-\dfrac{3}{5}=-\dfrac{16}{35}\)
\(\Rightarrow x=-\dfrac{16}{35}:\dfrac{3}{5}=-\dfrac{16}{21}\)
Vậy : \(x=-\dfrac{16}{21}\)
\(c.\)
\(\dfrac{3}{4}x+\dfrac{1}{2}=-\dfrac{3}{5}\)
\(\Rightarrow\dfrac{3}{4}x=-\dfrac{3}{5}-\dfrac{1}{2}=-\dfrac{11}{10}\)
\(\Rightarrow x=-\dfrac{11}{10}:\dfrac{3}{4}=-\dfrac{22}{15}\)
Vậy : \(x=-\dfrac{22}{15}\)
\(d.\)
\(-\dfrac{2}{15}-x=-\dfrac{3}{10}\)
\(\Rightarrow x=-\dfrac{2}{15}-\left(-\dfrac{3}{10}\right)=\dfrac{1}{6}\)
Vậy : \(x=\dfrac{1}{6}\)
Bài 1:
a, \(\frac{1}{-16}-\frac{3}{45}=\frac{-1}{16}-\frac{1}{15}\)
\(=\frac{-15}{240}-\frac{16}{240}\)
\(=\frac{-31}{240}\)
b, \(=\frac{-10}{12}-\frac{-12}{12}\)
\(=\frac{2}{12}=\frac{1}{6}\)
c, \(=\frac{-30}{6}-\frac{1}{6}\)
\(=\frac{-31}{6}\)
Bài 2:
a, \(x=-\frac{1}{2}-\frac{3}{4}\)
\(x=-\frac{1}{4}\)
b, \(\frac{1}{2}+x=-\frac{11}{2}\)
\(x=-\frac{11}{2}-\frac{1}{2}\)
\(x=-6\)
Bạn nhớ k đúng và chọn câu trả lời này nhé!!!! Mình giải đúng và chính xác hết ^_^
a,\(\frac{1}{x-1}+\frac{-2}{3}.\left(\frac{3}{4}-\frac{6}{5}\right)=\frac{5}{2-2x}\)
\(\Rightarrow\frac{1}{x-1}+\frac{-2}{3}.\left(\frac{3}{4}-\frac{6}{5}\right)=\frac{5}{2-2x};Đkxđ:x\ne1\)
\(\Rightarrow\frac{1}{x-1}+\frac{-2}{3}\left(\frac{-9}{20}\right)=\frac{5}{2-2x}\)
\(\Rightarrow\frac{1}{x-1}+\frac{3}{10}=\frac{5}{2-2x}\)
\(\Rightarrow\frac{1}{x-1}-\frac{5}{2-2x}=\frac{-3}{10}\)
\(\Rightarrow\frac{1}{x-1}-\frac{5}{-2\left(x-1\right)}=\frac{-3}{10}\)
\(\Rightarrow\frac{1}{x-1}+\frac{5}{2\left(x-1\right)}=\frac{3}{10}\)
\(\Rightarrow\frac{7}{2\left(x-1\right)}=\frac{-3}{10}\)
\(\Rightarrow70=-6\left(x-1\right)\)
\(\Rightarrow6x=6-70\)
\(\Rightarrow6x=-64\)
\(\Rightarrow x=\frac{-32}{3}x\ne1\)
a) \(\frac{x-3}{5}=\frac{2x-5}{45}\)
=> \(\left(x-3\right)\cdot45=5\left(2x-5\right)\)
=> \(45x-135=10x-25\)
=> \(45x-10x=-25+135\)
=> \(35x=110\)
=> \(x=\frac{110}{35}=\frac{22}{7}\)
b) \(\frac{x}{3}=\frac{y}{4}\)và x + 2y = 33
=> \(\frac{x}{3}=\frac{2y}{8}\)và x + 2y = 33
Áp dụng tính chất dãy tỉ số bằng nhau ta có :
\(\frac{x}{3}=\frac{2y}{8}=\frac{x+2y}{3+8}=\frac{33}{11}=3\)
\(\frac{x}{3}=3\Rightarrow x=9\)
\(\frac{2y}{8}=3\Rightarrow2y=24\Rightarrow y=12\)
a) 5 + 45(2x - 1) = 10
45(2x - 1) = 10 - 5
45(2x - 1) = 5
2x - 1 = 5 : 45
2x - 1 = 1/9
2x = 1/9 + 1
2x = 10/9
x = 10/9 : 2
x = 5/9
b) 54 : (2ˣ⁻³ + 1) + 3 = 9
54 : (2ˣ⁻³ + 1) = 9 - 3
54 : (2ˣ⁻³ + 1) = 6
2ˣ⁻³ + 1 = 54 : 6
2ˣ⁻³ + 1 = 9
2ˣ⁻³ = 9 - 1
2ˣ⁻³ = 8
2ˣ⁻³ = 2³
x - 3 = 3
x = 3 + 3
x = 6
c) 14 + 36 : 3ˣ⁻⁵ = 18
36 : 3ˣ⁻⁵ = 18 - 14
36 : 3ˣ⁻⁵ = 4
3ˣ⁻⁵ = 36 : 4
3ˣ⁻⁵ = 9
3ˣ⁻⁵ = 3²
x - 5 = 2
x = 2 + 5
x = 7
a: =>45(2x-1)=5
=>2x-1=1/9
=>2x=10/9
=>x=5/9
b: =>\(\dfrac{54}{2^{x-3}+1}=6\)
=>\(2^{x-3}+1=9\)
=>\(2^{x-3}=8\)
=>x-3=3
=>x=6
c: \(14+36:3^{x-5}=18\)
=>\(\dfrac{36}{3^{x-5}}=18-14=4\)
=>\(3^{x-5}=9\)
=>x-5=2
=>x=7