y= -2x+4, -x+3y=-9
Solve the following system:
{y = 4-2 x
3 y-x = -9
Substitute y = 4-2 x into the second equation:
{y = 4-2 x
3 (4-2 x)-x = -9
3 (4-2 x)-x = (12-6 x)-x = 12-7 x:
{y = 4-2 x
12-7 x = -9
In the second equation, look to solve for x:
{y = 4-2 x
12-7 x = -9
Subtract 12 from both sides:
{y = 4-2 x
-7 x = -21
Divide both sides by -7:
{y = 4-2 x
x = 3
Substitute x = 3 into the first equation:
{y = -2
x = 3
Collect results in alphabetical order:
Answer: | x = 3 and y=-2
