Question

Answer 1

`a,x: 0,2 = 0,8 :x`

`=> x/(0,2) =(0,8)/x`

`=> x^2 =0,2 . 0,8`

`=>x^2=0,16`

`=>x^2=(+-0,4)^2`

`=> x=0,4` hoặc `x=-0,4`

`b,x: 2,5= 0,03 : 0,75`

`=> x: 2,5=0,04`

`=>x=0,04 . 2,5`

`=>x=0,1`

`c, 10 1/2 : 2 1/4 = 14 : (2x-1)`

`=> (10 . 2+1)/2 : (2.4+1)/4 = 14 : (2x-1)`

`=> 21/2 : 9/4 =14 : (2x-1)`

`=> 14 : (2x-1) =21/2 . 4/9`

`=> 14:(2x-1)=14/3`

`=> 2x-1=14:14/3`

`=> 2x-1=14 . 3/14`

`=> 2x-1=3`

`=>2x=3+1`

`=>2x=4`

`=>x=2`

`d,15:(-2x)=5:(-0,4)`

`=>15:(-2x)=-12,5`

`=> -2x=15:(-12,5)`

`=>-2x=-1,2`

`=>x=-1,2 : (-2)`

`=>x=0,6`

Answer 2

a: =>x^2=0,16

=>x=0,4 hoặc x=-0,4

b: =>x=1/25*2,5=1/25*5/2=5/50=1/10

c: =>14:(2x-1)=10,5:2,25=14/3

=>2x-1=3

=>2x=4

=>x=2

d: =>15/-2x=5/-0,4=-25/2

=>2x=6/5

=>x=3/5