Question 837974
Solution  : 
 	
The substitution method is used to eliminate one of the variables by replacement when solving a system of equations.

(1)

3x - 11y = 16..........(1) 
x + y = 3..............(2)
We can write the (2) equation as  x = 3 - y 
Substituting the value x in equation (1) we get , 
3x - 11y = 16
3(3 - y ) - 11y = 16
9 - 3y - 11y = 16 
9 - 14y = 16
-14y = 16 - 9
-14y = 7
So  y = -1/2
Replug the y=-1/2 in (2) we get , 
x - 1/2 = 3 
x = 3+1/2
x = 7/2 
So we have the value as  x = 7/2 and y = -1/2


(2)  

 4x - y = 4.......(1) 
 x + 2y = 10......(2)
from (2)  x = 10 - 2y
Plug it in (1) 
4(10 - 2y) - y = 4
40 - 8y - y = 4
40 - 9y = 4
-9y = -40 + 4
-9y = -36
 y = 4
Replug in equation (2)
x+ 2y = 10
x + 2(4) = 10
x = 10 - 8
x = 2


So we have the value as  x = 2 and y = 4

Thank you.