Question

срочно хелп поможіть​

Answer 1

$\displaystyle\bf\\1)\\\\\frac{a}{b-1} +\frac{5}{b-1} =\frac{a+5}{b-1}$

Ответ : Д

$\displaystyle\bf\\2)\\\\\frac{a}{1-b} -\frac{5}{b-1}=\frac{a}{1-b} +\frac{5}{1-b} =\frac{a+5}{1-b}$

Ответ : B

$\displaystyle\bf\\3)\\\\\frac{5a}{a-b} +\frac{5b}{b-a}=\frac{5a}{a-b} -\frac{5b}{a-b} =\frac{5\cdot(a-b)}{a-b}=5$

Ответ : A

$\displaystyle\bf\\4)\\\\\frac{5a}{2b-a} +\frac{10b}{a-2b}=\frac{5a}{2b-a} -\frac{10b}{2b-a} =\frac{5\cdot(a-2b)}{2b-a} = -\frac{5\cdot(a-2b)}{a-2b} = -5$

Ответ : Г

$\displaystyle\bf\\5)\\\\\sqrt{12\Big(3-\sqrt{10} \Big)^{2} } =\sqrt{4\cdot 3\cdot \Big(3-\sqrt{10} \Big)^{2} } =2\cdot \Big|3-\sqrt{10} \Big|\cdot\sqrt{3} =\\\\\\=2\cdot\Big(\sqrt{10} -3\Big)\cdot \sqrt{3} =2\sqrt{30} -6\sqrt{3}$