Question

{x-y=4 Sisteme
{x+2y=1


b) {x+2y=8
{x-y= -1
c) {3x-y=12
{x-y=2

d) {x-y=6
{x+3y= -2

e) {2x-y=9
{x+2y=2

f) {x+2y=2
{x-y= -4

Answer 1

{x-y=4  {x+2y=1
y=x-4
x+2(x-4)=1
x+2x-8=1
3x=9
x=3
y=3-4=-1


b) {x+2y=8
{x-y= -1
y=x+1
x+2(x+1)=8
x+2x+2=8
3x=6
x=2
y=2+1=3

c) {3x-y=12
{x-y=2
y=x-2
3x-(x-2)=12
3x-x+2=12
2x=10
x=5
y=5-2=3

d) {x-y=6
{x+3y= -2
y=x-6
x+3(x-6)=-2
x+3x-18=-2
4x=16
x=4
y=4-6=-2
e) {2x-y=9
{x+2y=2

f) {x+2y=2
{x-y= -4 y=x+4
x+2(x+4)=2
x+2x+8=2
3x=-6
x=-2
y=-2+4=2