Question

7x+10y=3 2×-5y=-7 siteme de ecuatii​

Answer 1

$\begin{cases}7x + 10y = 3 \\ 2x - 5y = - 7\big|\cdot2 \end{cases} \\ \\ \begin{cases}7x + 10y = 3 \\ 4x - 10y = - 14\end{cases} \\ \iff 7x + 4x = 3 - 14 \\ 11x = - 11 \\ x = - 1 \\ \implies 2\cdot( - 1) - 5y = - 7\implies -5y = - 5 \\ \implies y = 1 \\ \\ \text{raspuns : } \\ x = - 1 \\ y = 1 \: \: \: \:$