Răspuns :

Danaradu70id

Răspuns:

x= - 4

y=4

Explicație pas cu pas:

din a doua  ecuatie rezulta   x=8-3y

inlocuiesc in prima ecuatie dupa ce aduc la acelasi numitor amplificand a doua fractie cu 2

(x-6y)/4=-7

deci x-6y=-4*7=-28

8-3y-6y=-28

-9y=-28-8

-9y=-36

y=36/9=4

y=4

x=8-3*4=8-12

x=-4

Targoviste44id

[tex]\it \begin{cases}\it \dfrac{1}{4}x-\dfrac{3}{2}y=-7|_{\cdot4} \Rightarrow x-6y=-28\\ \\ \\ \it x+3y=8 \Rightarrow x=8-3y\ \ \ \ \ (*)\end{cases}\\ \\ \\ x-6y=-28\ \stackrel{(*)}{\Longrightarrow}\ 8-3y-6y=-28|_{-8} \Rightarrow -3y-6y=-36 \Rightarrow \\ \\ -9y=-36|_{{:(-9)}} \Rightarrow y=4[/tex]

[tex]\it y=4\ \stackrel{(*)}{\Longrightarrow}\ x=8-3\cdot4 \Rightarrow x=8-12 \Rightarrow x=-4\\ \\ \\ S=\{(-4,\ \ 4)\}[/tex]