Question

Rezolvati in multimea numerelor reale prin metoda reducerii sistemului de ecuatii.urgent va rog
4x-y=-1;
2x+y=13

Answer 1

Aduni cele doua relatii si obtii:
6x=12
x=2 si inlocuiesti in prima relatie:
4*2-y=-1
y=8+1
y=9

Answer 2

      
$4x - y = -1 \\ 2x +y=13 \\ \text{-------------------- Adunam ecuatiile:} \\ 6x \;\;\;\; /\,= 12 \\ x= \frac{12}{6}=\boxed{2} \\ 2x +y=13 \\ y=13-2x=13-2*2=13-4=\boxed{9}$


$\text{Problema atasata ulterior: } \\ 3x+2y=19 \;\;\;\;|\;*(-1)\\ x+5y=15 \;\;\;\;|\;*3\\ --- \\ -3x-2y=-19 \\ 3x+15y=45 \\ \text{-------------------------- Adunam ecuatiile} \\ /\;\;\;\;\;\;\;13y = 26 \\ y = \frac{26}{13}=\boxed{2} \\ x=15-5y = 15-5*2=15-10=\boxed {5}$