Question

{x + y=14
{x + 3y=20

{x - 2y=3
{x + 4y=9

{x + y=2
{ y=3x

{2x + y=10
{x + 2y=11

Answer 1

{x + y=14--->y=14 -x
{x + 3y=20

x+3y=20
x+3*(14-x)=20
x+42-3x=20
x-3x=20-42
-2x= -22
x=11

x+y=14
11+y=14
y=14-11
y=3

s (11 , 3 )

{x - 2y=3---->-2y=3-x
{x + 4y=9

x+4*(3-x)=9
x+12-4x=9
x-4x=9-12
-3x= -3
x= 1

x + 4y=9
1+4y=9
4y=9-1
4y= 8
y=8/4
y= 4

s (1 ,4)

{x + y=2----->y=2-x
{ y=3x

2-x=3x
-x-3x= -2
-4x= -2
x=2/4
x=1/2

y=3x
y=3*1/2
y=3/2

s ( 1/2 , 3/2 )

{2x + y=10---->y=10-2x
{x + 2y=11

x+2*(10-2x)=11
x+20--4x=11
x-4x=11-20
-3x= -9
x= 9/3
x= -3

x + 2y=11

3+2y=11
2y=11-3
2y=8
y=8/2
y=4

s ( 3 , 4 )