Find the solution of this system of equations x-7y=-20 - 3x+9y=36

Solve the following system using elimination:

{x - 7 y = - 20 | (equation 1)

{9 y - 3 x = 36 | (equation 2)

Swap equation 1 with equation 2:

{ - (3 x) + 9 y = 36 | (equation 1)

{x - 7 y = - 20 | (equation 2)

Add 1/3 * (equation 1) to equation 2:

{ - (3 x) + 9 y = 36 | (equation 1)

{0 x - 4 y = - 8 | (equation 2)

Divide equation 1 by 3:

{-x + 3 y = 12 | (equation 1)

{0 x - 4 y = - 8 | (equation 2)

Divide equation 2 by - 4:

{-x + 3 y = 12 | (equation 1)

{0 x+y = 2 | (equation 2)

Subtract 3 * (equation 2) from equation 1:

{-x+0 y = 6 | (equation 1)

{0 x+y = 2 | (equation 2)

Multiply equation 1 by - 1:

{x+0 y = - 6 | (equation 1)

{0 x+y = 2 | (equation 2)

Collect results:

Answer: {x = - 6

{y = 2