=1x0.5:X+0.4:X = 18+0.3:X

=0.5:X+0.4:X = 18+0.3:X

=(0.5+0.4):X = 18+0.3:X

=0.9:X = 18+0.3:X

18=(0.9-0.3):X

18=0.6:X

X=18:0.6

X=30

    100%x-50%:x+40%:x=18+30%:x

<=>x-x/2+2/5x=18+3/10x

<=>10x²-5x²+4=180x+3

<=>10x²-5x²+4-180x-3

<=>5x²-180x+1=0

Denta=(-180)²-4.5.1=32380

Phương trình có 2 nghiệm phân biệt :

x¹=180+căn32380/10;x²=180-căn32380/10

100%:x-50%:x+40%:x=18+30%:x

<=> (100% - 50% + 40%) : x = 18 + 30% : x

<=> 90% : x = 18 + 30% : x 

=> 90% : x - 30% : x = 18

=> (90% - 30%) : x = 18

<=> x = 60% : 18

=> x = \(\frac{1}{30}\)

100%:x-50%:x+40%:x=18+30%:x

<=> (100% - 50% + 40%) : x = 18 + 30% : x

<=> 90% : x = 18 + 30% : x 

=> 90% : x - 30% : x = 18

=> (90% - 30%) : x = 18

<=> x = 60% : 18

=> x = 1/30

Học tốt nha! Love❤

Cảm ơn nhà Mik tick rồi

tìm x biết 

100% : x - 50% : x + 40 % : x = 18 + 30% 

1 : x - 0.5 + 0.4 : x = 18 + 0.3

( 1 - 0.5 + 0.4 ) : x = 17.7

0.9 : x = 17.7

       x = 0.9 : 17.7

      x = \(\frac{3}{59}\)

a; 100% : \(x\) - 50% : \(x\) + 40% : \(x\) = 18 + 30% : \(x\)

   (100% - 50% + 40%): \(x\) = 18 + 30% : \(x\)

                            90% : \(x\)  = 18 + 30% : \(x\)                  

                           90%: \(x\)  - 30%: \(x\) = 18

                          60% : \(x\) = 18

                                   \(x\) = 60% : 18

                                    \(x\) = \(\dfrac{1}{30}\)

B)

( x + 4/3 ) * 7/4 = 5 - 7/6

( x + 4/3) * 7/4 = 5/1 - 7/6

( x + 4/3) * 7/4 = 30/6 - 7/6

( x + 4/3) * 7/4 = 23/6 

( x + 4/3)        = 23/6 : 7/4

( x+ 4/3)         = 23/6 . 4/7

( x+ 4/3)         = 46/21

  x                 = 46/21 - 4/3

  x                  = 46/21 - 28/21

 x                 =  18/21 = 6/7
Tk vs kb hộ mk nha! thank u 

may cau khac ko kho lam dau chi co cau d thoi.

(100%-50%+40%):x=18%+30%:x

90%:x=18%+30%:x

18%=90%:x-30%:x

18%=60%:x

X=60%:18%

x=..................................................................................................

xong roi do  a cho minh nhe

a) 

( x - 1/2) * 5/3 = 7/4   - 1/2

( x - 1/2) * 5/3 = 7/4  - 2/4

( x - 1/2) * 5/3 = 5/4

( x - 1/2)        = 5/4 : 5/3

( x - 1/2 )      = 5/4 . 3/5

( x - 1/2 )      = 3/4

  x               = 3/4 + 1/2

  x               = 3/4 + 2/4

  x              = 5/4

Tk + kb hộ mk nha! thanks        

a)

\(\frac{x}{18}=\frac{y}{15},x-y=-30\)

\(\frac{x}{18}=\frac{y}{15}\)

\(\frac{x}{18}-\frac{y}{15}=0\)

\(-\frac{6y-5x}{90}=0\)

\(6y-5x=0\)

\(x-y=-30\)

\(-\left(y-x-30\right)=0\)

\(y-x-30=0\)

\(\Rightarrow x=-180;y=-150\)

dẫn tui bài y:9-8=15 với