Giải thích các bước giải:
l.$2x-\sqrt[]{6x-x^2-5}=6$
$\rightarrow 2x-6=\sqrt[]{6x-x^2-5}(\rightarrow x\ge 3)$
$\rightarrow (2x-6)^2=(\sqrt[]{6x-x^2-5})^2$
$\rightarrow 4x^2-24x+36=6x-x^2-5$
$\rightarrow 5x^2-30x+41=0$
$\rightarrow x=\dfrac{15+2\sqrt[]{5}}{5}\text{ (Do }x\ge 3)$
m.$x-\sqrt[]{2x-5}=4$
$\rightarrow x-4=\sqrt[]{2x-5}\rightarrow (x\ge 4)$
$\rightarrow (x-4)^2=2x-5$
$\rightarrow x^2-8x+16=2x-5$
$\rightarrow x^2-10x+21=0$
$\rightarrow (x-7)(x-3)=0$
$\rightarrow x=7\quad Do\quad x\ge 4$
