Solve the following system using elimination:
 
{5 y - 2 x = -42 | (equation 1) 
 
7 x + 2 y = 30 | (equation 2) 
 
 
Swap equation 1 with equation 2: 
 
{7 x + 2 y = 30 | (equation 1) 
 
-(2 x) + 5 y = -42 | (equation 2) 
 
 
Add 2/7 × (equation 1) to equation 2: 
 
{7 x + 2 y = 30 | (equation 1) 
 
0 x+(39 y)/7 = (-234)/7 | (equation 2) 
 
 
Multiply equation 2 by 7/39: 
 
{7 x + 2 y = 30 | (equation 1) 
 
0 x+y = -6 | (equation 2) 
 
 
Subtract 2 × (equation 2) from equation 1: 
 
{7 x+0 y = 42 | (equation 1) 
 
0 x+y = -6 | (equation 2) 
 
 
Divide equation 1 by 7: 
 
{x+0 y = 6 | (equation 1) 
 
0 x+y = -6 | (equation 2) 
 
 
Collect results: 
 
 
Answer: {x = 6, y = -6