Solve the following system:
{x+3 y = 18 | (equation 1)
-x-4 y = -25 | (equation 2)
Add equation 1 to equation 2:
{x+3 y = 18 | (equation 1)
0 x-y = -7 | (equation 2)
Multiply equation 2 by -1:
{x+3 y = 18 | (equation 1)
0 x+y = 7 | (equation 2)
Subtract 3 × (equation 2) from equation 1:
{x+0 y = -3 | (equation 1)
0 x+y = 7 | (equation 2)
Collect results:
Answer: | x = -3 and y=7
