Question

Решите пж
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Answer 1

$12)\frac{1}{5}x^{2}=16\\\\x^{2}=16:\frac{1}{5}=16*5=80\\\\x_{1}=-\sqrt{80}=-4\sqrt{5}\\\\x_{2}=\sqrt{80}=4\sqrt{5}$

$13)\frac{12}{\sqrt{x-3}}=6\\\\\left \{ {{\sqrt{x-3}=12:6 } \atop {x-3>0}} \right.\\\\\\\left \{ {{\sqrt{x-3}=2 } \atop {x>3}} \right.\\\\x-3=4\\\\x=7$

$14)(x-1,6)^{2}-2,25=0\\\\(x-1,6)^{2} =2,25\\\\(x-1,6)^{2}=1.5^{2}\\\\\left[\begin{array}{ccc}x-1,6=-1,5\\x-1,6+1,5\end{array}\right\\\\\\\left[\begin{array}{ccc}x_{1}=0,1 \\x_{2}=3,1 \end{array}\right$

$15)\sqrt{6-15x}=6\\\\(\sqrt{6-15x})^{2}=6^{2}\\\\6-15x=36\\\\-15x=30\\\\x=-2\\\\Proverka:\\\\\sqrt{6-15*(-2)}=6\\\\\sqrt{36}=6\\\\6=6-verno\\\\Otvet:-2$

$16)(\sqrt{5}x)^{2}=3\\\\5x^{2}=3\\\\x^{2}=\frac{3}{5}=0,6\\\\x_{1,2} =\pm\sqrt{0,6}$