Question

a și d repede va rog​

Answer 1

a)

$\begin{cases}x+3y=7 \\-x+5y=9 \end{cases}$

$3y + 5y = 7 + 9 \iff 8y = 16 \implies y = 2$

$x + 3 \cdot 2 = 7 \iff x = 7 - 6 \implies x = 1$

$\implies \begin{cases}x = 1 \\y = 2 \end{cases}$

d)

$\begin{cases}4x - 7y = 11 \\6x + 7y = - 1 \end{cases}$

$4x + 6x = 11 - 1 \iff 10x = 10 \implies x = 1$

$6 \cdot 1 + 7y = - 1 \iff 7y = - 7 \implies y = - 1$

$\implies \begin{cases}x = 1 \\y = -1 \end{cases}$