Question

Answer 1

`\sqrt{9x+9}-\sqrt{25x+25}+\sqrt{36x+36}=8`      `ĐK: x >= -1`

`<=>3\sqrt{x+1}-5\sqrt{x+1}+6\sqrt{x+1}=8`

`<=>4\sqrt{x+1}=8`

`<=>\sqrt{x+1}=2`

`<=>x+1=4`

`<=>x=3` (t/m)

Answer 2

a) \(\sqrt{9x+9}-\sqrt{25x+25}+\sqrt{36x+36}=9\)

\(3\sqrt{x+1}-5\sqrt{x+1}+6\sqrt{x+1}=8\)

\(4\sqrt{x+1}=8\)

\(\sqrt{x+1}=\dfrac{8}{4}\)

\(\sqrt{x+1}=2\)

\(x+1=2^2\)

\(x+1=4\)

`=>x=3`