Question

Допоможіть зробити 7 і 8.Будь ласка

Answer 1

$7)(1-5\sqrt{7})^{2}+10\sqrt{7}=1-10\sqrt{7}+175+10\sqrt{7}=\boxed{176}\\\\\\8)\frac{1}{4} \sqrt{12-2x}-1=0\\\\\sqrt{12-2x}=4\\\\(\sqrt{12-2x})^{2} =4^{2}\\\\12-2x=16\\\\2x=12-16\\\\2x=-4\\\\\boxed{x=-2}\\\\Proverka:\\\\\frac{1}{4}\sqrt{12-2*(-2)}-1=0\\\\\frac{1}{4}\sqrt{12+4} -1=0\\\\\frac{1}{4}\sqrt{16}-1=0\\\\\frac{1}{4}*4-1=0\\\\1-1=0\\\\0=0-verno\\\\Otvet:\boxed{x=-2}$