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( 2 3/4 - 1 4/5 ) x = 1
=> ( 11/4 - 9/5 ) x = 1
=> 19/20 x = 1
=> x = 1 : 19/20
=> x = 20/19
x^2 - 9 .( 3 - 5x ) = 0
=> x^-7 . ( 3 - 5x ) = 0
=> x^-7 = 0 hoặc 3 - 5x = 0
=> Mà x^-7 = 0 => x loại
=> 3 - 5x = 0
=> 5x = 3 - 0 = 3
=> x = 3 : 5
=> x = 3/5
a) Ta có: \(\left(x-\frac{1}{3}\right)^2-\frac{1}{4}=0\)
\(\Rightarrow\left(x-\frac{1}{2}\right)^2=\frac{1}{4}\)
\(\Rightarrow x-\frac{1}{2}=\frac{1}{2}\Rightarrow x=1\)
hoặc \(x-\frac{1}{2}=-\frac{1}{2}\Rightarrow x=-\frac{1}{2}+\frac{1}{2}=0\)
Vậy \(x\in\left\{1;0\right\}\)
b)\(20\%.x+\frac{2}{5}x=x-4\)
\(\Rightarrow\frac{1}{5}x+\frac{2}{5}x-x=-4\)
\(\Rightarrow\frac{-2}{5}x=-4\)
\(\Rightarrow x=-4:\left(-\frac{2}{5}\right)=10\)
Vậy x=10
c) 3(x+1)+4(x+3)-2(x+16) = 18
=> 3x+3+4x+12-2x-32 =18
=> (3x+4x-2x)+(3+12-32)=18
=> 5x - 17 = 18
=> 5x = 18 + 17 = 35
=> x = 35 : 5 = 7
Vậy x = 7
a)100-7.[x-5]=58
7.[x-5]=100-58=42
x-5=42:7=6
x=6+5
x=11
b)12.[x-1]:3=43+23
12 [x-1]:3=64+8
12.[x-1]:3=72
[x-1]:3=72:12=6
[x-1]=6.3=18
x=18-1
x=17
tao koooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo biếtttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt
a. \(\frac{1}{3}x-\frac{2}{5}=\frac{2}{3}x+1\)
\(\Leftrightarrow\frac{1}{3}x-\frac{2}{3}x=1+\frac{2}{5}\)
\(\Leftrightarrow-\frac{1}{3}x=\frac{7}{5}\)
\(\Leftrightarrow x=\frac{7}{5}\div\frac{-1}{3}\)
\(\Leftrightarrow x=\frac{21}{-5}\)
b. \(\frac{-4}{5}x+\frac{1}{3}=\frac{2}{3}x+\frac{1}{2}\)
\(\Leftrightarrow\frac{1}{3}-\frac{1}{2}=\frac{2}{3}x+\frac{4}{5}x\)
\(\Leftrightarrow\frac{-1}{6}=\frac{22}{15}x\)
\(\Leftrightarrow x=\frac{-1}{6}\div\frac{22}{15}\)
\(\Leftrightarrow x=\frac{-15}{132}\)
\(\left[\frac{4}{5}x+3\right]:\left(-4\right)=\frac{1}{2}\)
\(\frac{4}{5}x+3=\frac{1}{2}\times\left(-4\right)\)
\(\frac{4}{5}x+3=-2\)
\(\frac{4}{5}x=\left(-2\right)-3\)
\(\frac{4}{5}x=-5\)
\(x=\left(-5\right):\frac{4}{5}\)
\(x=-\frac{25}{4}\)
Chúc bạn học giỏi nhé!
Thi học kì thì cố lên !
4/5x + 3 = 1/2 . ( -4 )
4/5x + 3 = -4/2
4/5x = -4/2 - 3
4/5x = 5
x = 5 : 4/5
x = 25/4
vay x = 25/4
\(a)\left(3\frac{1}{2}-x\right).1\frac{1}{4}=\frac{15}{6}\)
\(\left(\frac{7}{2}-x\right).\frac{5}{4}=\frac{15}{6}\)
\(\frac{7}{2}-x=\frac{15}{6}:\frac{5}{4}\)
\(\frac{7}{2}-x=2\)
\(x=\frac{7}{2}-2\)
\(\Rightarrow x=\frac{3}{2}\)
\(a,\frac{1}{2}-\frac{2}{5}+3x=\frac{3}{4}\)
\(\frac{1}{10}+3x=\frac{3}{4}\)
\(3x=\frac{3}{4}-\frac{1}{10}\)
\(3x=\frac{13}{20}\)
\(x=\frac{13}{60}\)
\(b,2\cdot\left(\frac{3}{4}-5x\right)=\frac{4}{5}-3x\)
\(\frac{3}{2}-10x=\frac{4}{5}-3x\)
\(-10x+3x=\frac{4}{5}-\frac{3}{2}\)
\(-7x=\frac{-7}{10}\)
\(x=\frac{1}{10}\)
a)12(x-1)=0
=>x-1=0
=>x=1
b) 3/5x-3/4=(-3)2-|-11|
3/5x-3/4=9-11=-2
3/5x=-2+3/4=-5/4
=>x=-5/4:3/5=-25/12
c)4(x-5/8)-3/4=0,25
4(x-5/8)=0,25+3/4=1
=>x-5/8=1/4
x=1/4+5/8=7/8
2) Số đó là
27:3/5=45
làm mẫu nhé:
a) /4/5 - 1/5x/ - 2/3 = 1/5
=> /4/5 - 1/5x/ = 1/5 + 2/3 = 13/15
=> /4/5 - 1/5x/ = 13/15
/ 4/5 - 1/5x / = -13/15
=> 1/5x = 4/5 - 13/15 = -1/15 => x = -1/15 : 1/5 = -1/3
=> 1/5x = 4/5 - (-13/15) = 5/3 => x = 5/3 : 1/5 = 25/3
còn lại tương tự nha
\(\dfrac{1}{4}\left(\dfrac{2}{5}x-\dfrac{1}{4}\right)-\dfrac{3}{4}=-\dfrac{3}{2}\)
=>\(\dfrac{1}{4}\left(\dfrac{2}{5}x-\dfrac{1}{4}\right)=-\dfrac{3}{2}+\dfrac{3}{4}=\dfrac{-3}{4}\)
=>\(\dfrac{2}{5}x-\dfrac{1}{4}=-3\)
=>\(\dfrac{2}{5}x=-3+\dfrac{1}{4}=\dfrac{-11}{4}\)
=>\(x=-\dfrac{11}{4}:\dfrac{2}{5}=\dfrac{-11}{4}\cdot\dfrac{5}{2}=\dfrac{-55}{8}\)
\(\dfrac{1}{4}\cdot\left(\dfrac{2}{5}x-\dfrac{1}{4}\right)-\dfrac{3}{4}=-\dfrac{3}{2}\)
\(\Rightarrow\dfrac{1}{4}\cdot\left(\dfrac{2}{5}x-\dfrac{1}{4}\right)=-\dfrac{3}{2}+\dfrac{3}{4}\)
\(\Rightarrow\dfrac{1}{4}\cdot\left(\dfrac{2}{5}x-\dfrac{1}{4}\right)=\dfrac{-3}{4}\)
\(\Rightarrow\dfrac{2}{5}x-\dfrac{1}{4}=\dfrac{-3}{4}\cdot4\)
\(\Rightarrow\dfrac{2}{5}x-\dfrac{1}{4}=-3\)
\(\Rightarrow\dfrac{2}{5}x=-3+\dfrac{1}{4}\)
\(\Rightarrow\dfrac{2}{5}x=\dfrac{-35}{4}\)
\(\Rightarrow x=\dfrac{-11}{4}:\dfrac{2}{5}\)
\(\Rightarrow x=\dfrac{-55}{8}\)