Solve the following system:
{x+y = 12
2 x-y = 9
In the first equation, look to solve for y:
{x+y = 12
2 x-y = 9
Subtract x from both sides:
{y = 12-x
2 x-y = 9
Substitute y = 12-x into the second equation:
{y = 12-x
3 x-12 = 9
In the second equation, look to solve for x:
{y = 12-x
3 x-12 = 9
Add 12 to both sides:
{y = 12-x
3 x = 21
Divide both sides by 3:
{y = 12-x
x = 7
Substitute x = 7 into the first equation:
{y = 5
x = 7
Collect results in alphabetical order:
Answer: | {x = 7 and y=5
