Question

giúp mik

Answer 1

`1)sqrt{4x-4}-3=7`

`đk:4x-4>=0<=>x>=1`

`pt<=>sqrt{4x-4}=10`

BP 2 vế ta có:

`4x-4=100`

`<=>4x=104`

`<=>x=26(tm)`

Vậy `S={26}`

`4)sqrt{3x+1}-sqrt{x-1}=2`

`đk:x>=1`

`pt<=>sqrt{3x+1}=2+sqrt{x-1}`

BP 2 vế ta có:

`3x+1=x-1+4+4sqrt{x-1}`

`<=>3x+1=x+3+4sqrt{x-1}`

`<=>4sqrt{x-1}=2x-2`

`<=>2sqrt{x-1}=x-1`

`<=>sqrt{x-1}(sqrt{x-1}-2)=0`

`+)sqrt{x-1}=0<=>x=1`

`+)sqrt{x-1}=2<=>x=5`

Vậy `S={1,5}`