Solve the simultaneous equation
3x + y = 8
x - 3y = 11

x = 7 / 2, y = - 5 / 2

Step-by-step explanation:

3x + y = 8 > equation 1

3 ( 3x + y = 8 )

9x + 3y = 24 > equation 2

x - 3y = 11 > equation 3

Add equations 2 & 3,

9x + 3y = 24

x - 3y = 11

10x + 0 = 35

10x = 35

x = 35 / 10

x = 3.5

Substitute x = 3.5 in equation 1,

3x + y = 8

3 ( 3.5 ) + y = 8

10.5 + y = 8

y = 8 - 10.5

y = - 2.5

x = 3.5

= 35 / 10

x = 7 / 2

y = - 2.5

= - 25 / 10

y = - 5 / 2