Question

помогите срочноооооооо​

Answer 1

$\displaystyle\bf\\\frac{21-7x}{27-3y} \cdot\frac{9-y}{4x-12} =\frac{7\cdot(3-x)\cdot(9-y)}{3\cdot(9-y)\cdot4\cdot(x-3)} =-\frac{7}{12} \\\\\\V=7 \ \ ; \ \ N=12$