Question

Решите систему уравнений

Answer 1

$\left \{ {(\frac{1}{5})^{4x-y}=25 } \atop {7^{9x-y}=\sqrt{7} }} \right. \\\\\\\\(\frac{1}{5} )^{4x-y}=25\\\\(5^{-1})^{4x-y}=5^{2}\\\\5^{y-4x}=5^{2}\\\\y-4x=2\\\\\\\\7^{9x-y}=\sqrt{7}\\\\ 7^{9x-y}=7^{1/2}\\\\9x-y=0.5\\\\\\\\\left \{ {{y-4x=2} \atop {9x-y=0.5}} \right. \\\\y-4x+9x-y=2+0.5\\\\5x=2.5\\\\x=0.5\\\\y-4*0.5=2\\\\y-2=2\\\\y=4$