SOLUTION: i'm not quite sure how to solve this using substitution. y=7-x y-x=3 I got(2,9) but i'm not quite sure if thats the right answer. Also, does the system have exactly one solu

Question 5474: i'm not quite sure how to solve this using substitution.
y=7-x
y-x=3
I got(2,9) but i'm not quite sure if thats the right answer.
Also, does the system have exactly one solution, or more?
Thanks for helping me!
Found 2 solutions by rapaljer, solver15:
Answer by rapaljer(4671) (Show Source): You can put this solution on YOUR website!
Because one of the equations is in the form "x = ____" or "y = ____", it is convenient to use the substitution method. Take the equation, and substitute this in place of the y in the second equation:

Now you just have a simple equation to solve for x.

Subtract 7 from each side of the equation:

Divide both sides by -2:

Now, to find y go back to the simplest equation (which is the "y = ___" equation:
, substitute x=2

So the point of solution is (2,5).

If when you solve for x and y in linear equations (that is, straight line equations), when you get an x or y value, that means there is only one point of intersection. If all the x's and y's subtract out, leaving you with no variables to solve for, then you have either NO SOLUTION (because the lines are parallel) or the solution is the entire line (becauses the equations actually represent the same line).

R^2 at SCC
Answer by solver15(27) (Show Source): You can put this solution on YOUR website!
y=7-x
y-x=3
(7-x)-x=3
7-x-x=3
7-2x=3
-7 -7
-2x/-2=-4/-2
x=2
then plug it back in to previous equation
y=7-(2)
y=7-2
y=5
=(2,5)

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