Question

Pr 9 ! Va rogggg!!!
Dau coroana!

Answer 1

$\begin{cases}\frac{x}{5} = \frac{y}{6} \big| \cdot \frac{1}{2} \\ \frac{y}{2} = \frac{z}{7} \big| \cdot \frac{1}{6} \end{cases} \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ \\ \\ a) \: \frac{x}{10} = \frac{y}{12} = \frac{z}{42} \implies \: \bold m = 42\\ \\ \\ \\ b)2x + y = z - x \\ \\ 2 \times \frac{5y}{6} + y = \frac{7y}{2} - \frac{5y}{6} \\ \\ \frac{10y}{6} + \frac{6y}{6} = \frac{21y}{6} - \frac{5y}{6} \\ \\ 10y + 6y = 21y - 5y \\ 16y = 16y \\ y = y \\ \implies \: y\in\mathbb{R} \\ \implies\large \: \bold{adevărat}$