Question

Exercitiul numarul 2

Answer 1

a) 
{5x+y=7
{3x-y=8 le aduni
8x \ =15
x=15\8    y=7-5x15\8=7-75\8=56-75\8=19\8
b)
{3x+3y=0
{5x-y=12  \ x3
{3x+3y=0
{15x-3y=36 le aduni
18x \ =36
x=36\18=2   3y=3x2=6  y=6\3=2
c)
{4x+3=5-3y
{x-y=0
{4x+3y=2
{x-y=0 \x3
{4x+3y=2
{3x-3y=0
7x \ =2
x=2\7  -y=-2\7 y=2\7
d)
{7x-y=16 \x2
{3x+2y=2  
{14x-2y=36
{3x+2y=2 le aduni
17x \ =38
x=38\17