Answer: 
{x,y}={ 1/2, 5)
Explanation:
 [1] 8x + 7y = 39
 [2] 4x - 14y = -68
Solve equation [2] for the variable x 
 
 [2] 4x = 14y - 68
 [2] x = 7y/2 - 17
// Plug this in for variable x in equation [1]
 [1] 8•(7y/2-17) + 7y = 39
 [1] 35y = 175
// Solve equation [1] for the variable y 
 [1] 35y = 175 
 [1] y = 5 
// By now we know this much :
 x = 7y/2-17
 y = 5
// Use the y value to solve for x 
 x = (7/2)(5)-17 = 1/2