Question

Помогите, пожалуйста, решить систему $left { {{ frac{1}{5} ^{4x-y}=25 } atop {7 ^{9x-y}= sqrt{7} }} right.$

Answer 1

$left { {{ frac{1}{5} ^{4x-y}=25 } atop {7 ^{9x-y}= sqrt{7} }} right. Rightarrow left { {5^{y-4x}=5^2 } atop {7 ^{9x-y}=7^{1/2}}} right. Rightarrow left {y-4x=2 } atop {9x-y= frac{1}{2} } right. Rightarrow$
$left {y=2+4x } atop {9x-2-4x= frac{1}{2} } right. Rightarrow left {y=2+4x } atop {5x=2frac{1}{2} } right. Rightarrow left {y=2+4x } atop {x=0,5 } right. Rightarrow left {y=4 } atop {x=frac{1}{2} } right.$