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Hứa k r lm cko! Bài dài lắm

( 0,25x ) : 3 = 5/6 : 0,125

( 1/4x ) : 3 = 5/6 : 1/8

( 1/4x ) : 3 = 5/6 x 8

( 1/4x ) : 3 = 20/3

1/4x          = 20/3 x 3

1/4x         = 20

x              = 20 : 1/4

x              = 80

0,01 : 2,5 = ( 0,75x ) : 0,75

1/100 : 25/10 = (3/4x) : 3/4

1/100 x 10/25 = (3/4x) : 3/4

=>(3/4x) : 3/4 = 1/250

3/4x                = 1/250 x 3/4

3/4x                = 3/1000

x                     = 3/1000 : 3/4

x                     = 1/250

 4/3 : 0,8 = 2/3 : ( 0,1x )

<=>2/3 : (0,1x) = 4/3 : 0,8

2/3 : (0,1x) = 4/3 : 4/5

2/3 : (0,1x) = 4/3 x 5/4

2/3 : (0,1x) = 5/3

2/3 : (1/10x) = 5/3

1/10x           = 2/3 : 5/3

1/10x           = 2/3 x 3/5

1/10x           = 2/5

x                  = 2/5 : 1/10

x                  = 2/5 x 10

x                  = 4

a) Lm r nkoa!

b) \(\left(0,25x\right):3=\frac{5}{6}:0,125\)

\(=\left(0,25x\right):3=\frac{20}{3}\)

\(\Rightarrow0,25x=\frac{20}{3}\cdot3=20\)

\(\Rightarrow x=20:0,25=80\)

\(\Rightarrow x=80\)

c) \(0,01:2,5=\left(0,75x\right):0,75\)

\(=\frac{1}{250}=\left(0,75x\right):0,75\)

\(\Rightarrow0,75x=\frac{1}{250}\cdot0,75=\frac{3}{1000}\)

\(\Rightarrow x=\frac{3}{1000}:0,75=\frac{1}{250}\)

\(\Rightarrow x=\frac{1}{250}\)

d) \(1\frac{1}{3}:0,8=\frac{2}{3}:\left(0,1x\right)\)

\(=\frac{5}{3}=\frac{2}{3}:\left(0,1x\right)\)

\(\Rightarrow0,1x=\frac{2}{3}:\frac{5}{3}=\frac{2}{5}\)

\(\Rightarrow x=\frac{2}{5}:0,1=4\)

\(\Rightarrow4\)

\(a,3,8:2x=\frac{1}{4}:2\frac{2}{3}\)

\(\Leftrightarrow3,8:2x=\frac{3}{32}\)

\(\Leftrightarrow2x=3,8:\frac{3}{32}\)

\(\Leftrightarrow2x=\frac{608}{15}\)

\(\Leftrightarrow x=\frac{304}{15}\)

\(b,0,25x:3=\frac{5}{6}:0,125\)

\(\Leftrightarrow0,25x:3=\frac{20}{3}\)

\(\Leftrightarrow0,25x=20\)

\(\Leftrightarrow x=80\)

\(c,0,01:2,5=0,75x:0,75\)

\(\Leftrightarrow0,75x:0,75=\frac{1}{250}\)

\(\Leftrightarrow x=\frac{1}{250}\)

Mik lm hơi tắt chỗ nào chw hiểu thì hỏi mik nhé

\(\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0\\ 4x^2-4x+1+x^2+6x+9-5x^2+245=0\\ 2x+255=0\\ 2x=-255\\ x=-\dfrac{255}{2}\)

       \(\frac{3}{8}.x+1=\frac{7}{8}\)                                                                           \(2012:x+23=526\)

\(\Leftrightarrow\frac{3}{8}.x=\frac{7}{8}-1\)                                                                  \(\Leftrightarrow2012:x=503\)

\(\Leftrightarrow\frac{3}{8}.x=\frac{-1}{8}\)                                                                        \(\Leftrightarrow x=4\)

\(\Leftrightarrow x=\frac{-1}{3}\)   

Câu a bạn viết lại đề đi nha khó nhìn quá

Câu b

2012 : x + 23= 526

 2012 : x = 526-23

2012: x=503

x=2012 : 503 

x =4

a. \(\frac{3}{8}.\)x + 1 =  \(\frac{7}{8}\)

\(\frac{3}{8}.\)x           = \(\frac{7}{8}-1\)

x                      = \(-\frac{1}{8}\): \(\frac{3}{8}\)

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

b. 2012 : x + 23 = 526

2012 : x             = 526 - 23

x                        = 2012 : 503

x                        = 4

b, x² +y²+z² +2x-4y-6z+14=0

<=> (x²+2x+1)+(y²-4y+4)+(z²-6z+9)=0

<=> (x+1)²+(y-2)²+(z-3)²=0

=>(x+1)²=(y-2)²=(z-3)²=0

=>x+1=y-2=z-3=0

=> x=-1; y=2; z=3

c, 2x²+y²-6x-4y+2xy+5=0

<=> (x²+y²+4+2xy-4x-4y)+(x²-2x+1)=0

<=> (x+y-2)²+(x-1)²=0

=> (x+y-2)²=(x-1)²=0

=>x+y-2=x-1=0

=>x=1; y=1