Question

\(\sqrt{2-x}-\sqrt{8-4x}+\sqrt{18-9x}=6\) giúp mik vs

Answer 1

Lời giải:
ĐKXĐ: $x\leq 2$

$\sqrt{2-x}-\sqrt{4(2-x)}+\sqrt{9(2-x)}=6$

$\Leftrightarrow \sqrt{2-x}-2\sqrt{2-x}+3\sqrt{2-x}=6$

$\Leftrightarrow (1-2+3)\sqrt{2-x}=6$

$\Leftrightarrow 2\sqrt{2-x}=6$

$\Leftrightarrow \sqrt{2-x}=3$

$\Leftrightarrow 2-x=3^2=9$

$\Leftrightarrow x=2-9=-7$ (tm)