Question

Помогите пожалуйста

Answer 1

$\left \{ {{7v+z=0} \atop {-z+5v=1}} \right. \\\\+\left \{ {{7v+z=0} \atop {5v-z=1}} \right. \\------\\12v=1\\\\v=\frac{1}{12} \\\\z=-7v=-7*\frac{1}{12} =-\frac{7}{12}\\\\Otvet:\\\\\boxed{z=-\frac{7}{12}} \\\\\boxed{v=\frac{1}{12}}$