Đáp án:
Giải thích các bước giải:
$11.x\sqrt{x}+\sqrt{x}-x-1$
$=\sqrt{x}(\sqrt{x}+1)-(\sqrt{x}-1)(\sqrt{x}+1)$
$=(\sqrt{x}+1)(\sqrt{x}-\sqrt{x}+1)$
$=(\sqrt{x}+1)$
$13,\sqrt{ab}-\sqrt{a}-\sqrt{b}+1$
$=\sqrt{b}(\sqrt{a}-1)-(\sqrt{a}-1)$
$=(\sqrt{a}-1)(\sqrt{b}-1)$
$15,2a-5\sqrt{ab}+3b$
$=2a-4\sqrt{ab}+2b-\sqrt{ab}+b$
$=2(a-2\sqrt{ab}+b)-\sqrt{b}(\sqrt{a}-\sqrt{b})$
$=2(\sqrt{a}-\sqrt{b})^2-\sqrt{b}(\sqrt{a}-\sqrt{b})$
$=(\sqrt{a}-\sqrt{b})(2\sqrt{a}-2\sqrt{b})$
$17,x^2-3x\sqrt{y}+2y$
$=x^2-2x\sqrt{y}+y-x\sqrt{y}+y$
$=(x-\sqrt{y})^2-\sqrt{y}(x-\sqrt{y})$
$=(x-\sqrt{y})(x-\sqrt{y}-\sqrt{y})$
$=(x-\sqrt{y})(x-2\sqrt{y})$
Chúc bạn học tốt.
