Đáp án:
$-\sqrt{7}-19\sqrt{11}$
Giải thích các bước giải:
$10\sqrt{28}-2\sqrt{275}-3\sqrt{343}-\dfrac{3}{2}\sqrt{396}$
$=10\sqrt{4.7}-2\sqrt{25.11}-3\sqrt{49.7}-\dfrac{3}{2}\sqrt{36.11}$
$=10.2\sqrt{7}-2.5\sqrt{11}-3.7\sqrt{7}-\dfrac{3}{2}.6\sqrt{11}$
$=20\sqrt{7}-10\sqrt{11}-21\sqrt{7}-9\sqrt{11}$
$=\sqrt{7}(20-21)-\sqrt{11}(10+9)$
$=-\sqrt{7}-19\sqrt{11}$