Question

giúp mình câu này

Answer 1

`a)\sqrt{x^2-4x+4}=7x-1`            `ĐK: x >= 1/7`

`<=>\sqrt{(x-2)^2}=7x-1`

`<=>|x-2|=7x-1`

`<=>[(x-2=7x-1),(x-2=1-7x):}`

`<=>[(6x=-1),(8x=3):}<=>[(x=-1/6(ko t//m)),(x=3/8(t//m)):}`

Vậy `S={3/8}`

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`b)2\sqrt{4x-8}-2/3\sqrt{9x-18}=\sqrt{49x-98}-10`     `ĐK: x>= 2`

`<=>4\sqrt{x-2}-2\sqrt{x-2}=7\sqrt{x-2}-10`

`<=>5\sqrt{x-2}=10`

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

`<=>x-2=4<=>x=6` (t/m)

Vậy `S={6}`