Answer:
1 Multiply the first equation by -1 then add the equations together
3. Multiply the second equation by -1 then add the equations together
4. Multiply the first equation by -2 then add the equations together
5. Multiply the first equation by 2 the second by -1 then add the equations together
Step-by-step explanation:
x+y = 7
2x+y = 5
1 Multiply the first equation by -1 then add the equations together
-x+-y = -7
2x+y = 5
---------------
x =-2 then solve for y
2. Multiply the second equation by -1 first equation by -1 then add the equations together
-x+-y = -7
-2x-y = -5
---------------
-3x -2y = -12
Still have both variables
3. Multiply the second equation by -1 then add the equations together
x+y = 7
-2x-y =- 5
----------------------
-x = 2
4. Multiply the first equation by -2 then add the equations together
-2x+-2y = -14
2x+y = 5
--------------
-y = -9
5. Multiply the first equation by 2 the second by -1 then add the equations together
2x+2y = 14
-2x-y = -5
--------------
y = 9
