Question

Срочно решите пожалуйста.​

Answer 1

$1)\left \{ {{x-y=4} \atop {5^{x+y} =25}} \right.\\\\\left \{ {{x-y=4} \atop {5^{x+y}=5^{2}}} \right.\\\\+\left \{ {{x-y=4} \atop {x+y=2}} \right.\\------\\2x=6\\x=3\\\\y=x-4=3-4=-1\\\\Otvet:\boxed {(3;-1)}$

$2)\left \{ {{(5^{x})^{y}=5^{21}} \atop {5^{x}*5^{y}=5^{10}}} \right.\\ 3^{x}>3^{y}\Rightarrow x>y\\\\\left \{ {{5^{xy}=5^{21}} \atop {5^{x+y}=5^{10}}} \right.\\\\\left \{ {{xy=21} \atop {x+y=10}} \right. \\\\\left \{ {{x=7} \atop {y=3}} \right.\\\\Otvet:\boxed {(7;3)}$