Question 97777: 3x+y=7
-4x-y=7
If they say solver for x and y, What are the steps inorder to solve for x and y? Answer by Msgenes(10) (Show Source):
You can put this solution on YOUR website! You solve this problem using the addition method so that one of the variables cancels out. In this case the problem is already set up so that one of the variables cancels out and that variable is y.
3x + y = 7
-4x - y = 7
............
-x = 14
Now that we have x by its self it can not be a negative. So we divid -1 on both sides.
-x = 14
.......
-1 -1
x = -14
Now that we have x we can find out what y is. I will use the first equation it does not matter which one you use to find y but the first equation involves less steps.
3x + y = 7
3(-14) + y = 7
-42 + y = 7
Now again we want y by it self and we do that by adding 42 to both sides.
-42 + 42 + y = 7 + 42
y = 49
The solution is (-14,49).
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